The answer is very little - often only as much as you can carry in one piece of luggage.

Over the last few days, we've been seeing images of Ukrainian refugees crossing borders on foot with as many of their belongings as they could cram into wheeled suitcases.

Image source, Reuters

Image source, AFP

Image source, Getty Images

Image source, Getty Images

Katya Adler
Europe Editor

Image source, Reuters

The crisis in Ukraine has already spurred the EU towards mini-revolutions considering its usual slowness to take action.

Brussels got rid of age-old taboos such as sending weapons to a country of war and applauding the rearming of post-World War Two Germany.

Now the taboo of taboos, known as energy security, looks like it may be smashed too. Russian violence against Ukraine is heaping pressure on the EU to impose energy sanctions. The bloc depends on Russia for 40% of its natural gas and a quarter of its oil imports.

What’s the point of all the EU’s financial sanctions, if Vladimir Putin’s war chest is filled on a daily basis with oil and gas revenues, you might ask?

So here we are: the US and Ukraine’s indefatigable President Zelensky are leaning on Brussels to slap sanctions on oil imports at least.

Eastern EU countries, like the Baltics, strongly agree. They feel particularly exposed by the Russian threat.

But other EU members, like big hitters Germany and Italy, feel more threatened by spiralling energy prices.

Emmanuel Macron of France is about to stand for re-election as president. He too is wary of making what could be unpopular moves amongst drivers and people needing to heat their homes.

So, for today, the EU has avoided talk of energy sanctions. Instead, it’s repeated plans to move as fast as possible from energy reliance on Russia: finding alternative suppliers and working on renewable energies.

But turning that wish into reality will take time - something Ukraine does not have.

If you're just joining our live coverage, here's a round-up of the latest key developments on day 12 of Russia's invasion of Ukraine.

• A third round of talks is set to be held between Ukrainian and Russian negotiators from 16:00 Kyiv time (14:00 GMT), according to Ukrainian officials

• A new Russian plan for a temporary ceasefire in Ukraine allowing civilians access to certain humanitarian corridors has been criticised - with the UK calling it "cynical beyond belief" and Ukraine branding it "immoral"
• Under Moscow's proposal, civilians fleeing Ukraine's capital Kyiv would be offered safe passage to Russia's ally Belarus, while those in Kharkiv will have a corridor leading only to Russia itself
• Evacuation routes from the besieged cities of Mariupol and Sumy will lead to other Ukrainian cities and to Russian ones
• Ukraine says Russian forces are targeting hospitals, nurseries and schools - and civilians have been caught up in the assault
• But Russia denies targeting civilians, saying it is carrying out a "special military operation" against Ukrainian "nationalists" and "neo-Nazis"
• Petrol prices have hit another record high as oil prices jumped to $139 a barrel while wholesale gas prices for next-day delivery more than doubled. The average price of a litre of petrol in the UK hit 155p for the first time
• It came as the US hinted at a ban on buying Russian energy, as it looked to other countries to increase supplies

• UK Prime Minister Boris Johnson is holding talks with the Canadian and Dutch prime ministers in London, as Western powers prepare to agree further sanctions on Russia
• Amid scrutiny of the UK's policy on Ukrainian refugees, Johnson insisted the government would be "very generous" to people fleeing the country but would not let them in without any checks

Image source, Ukrainian State Emergency Service

Our colleagues in BBC News Ukrainian have spoken to Oleg Revko, a doctor in the northern city of Chernihiv, which came under heavy fire from Russian troops.

Russia denies targeting civilians, but this Ukrainian doctor tells a different story. He says both his hospital and another in the city have been shelled.

“Hospitals are attacked like everything else, they don’t care", Oleg says.

He spent the first few days of the invasion hiding in the basement of his house on the outskirts of the city, less than a kilometre (0.62 miles) from an airfield where severe fighting took place.

“The house is right in the Russian line of fire," Oleg says. "I spent four days hiding from the shelling with eight of my neighbours. We used a bucket for a toilet.”

He managed to get out of the basement during a lull in fighting, and made it to his hospital in the city centre. Then the attacks got worse.

“They bring the injured to our hospital. People who lost their arms and legs, people with their guts hanging out. It’s not a pretty sight.”

He says he's decided to stay in the hospital for as long as he can.

“I’ll be in the hospital till the end. It is my duty. I don’t know how long the city will hold up. But I’ll be here with my people.”

Russia has said that it can stop operations at "any moment" if Ukraine meets Russian conditions.

Kremlin spokesman Dmitry Peskov says Ukraine must recognise Crimea as Russian, and Donetsk and Luhansk as independent states.

In addition to this, Peskov says Ukraine must amend its constitution and reject claims to enter any bloc (like Nato, for example).

He adds that Russia will finish the "demilitarisation" of Ukraine, and if these conditions are met Russian military action will "stop in a moment".

The Kremlin spokesman insists that Russia is not seeking to make any further territorial claims on Ukraine.

Russia seized and annexed Crimea in March 2014, and weeks later threw its support behind pro-Russian separatists in Ukraine's eastern Donetsk and Luhansk regions.

Joel Gunter
BBC News, Lviv

When Svitlana Maksymenko's train pulled into Kyiv, about halfway through her 800-mile journey from home to safety, people pushed onto every part of the carriage, she said, grasping for their own escape route west. Some abandoned their luggage. Some begged to get on.

"They were on their knees on the platform," Maksymenko says. "There was no room. There were people standing in every space, in every gangway, there were five people on every bed."

Maksymenko's journey began in Kharkiv, an eastern city that has been heavily shelled by Russian forces, and stopped, for now, in Lviv, a western city about 50 miles from the Polish border.

In almost every corner of the station concourse over the weekend, in the waiting rooms, the underpasses and all along the stretches of platform, there were people taking shelter, sleeping, anxiously waiting, rushing for trains.

Women with children wept with the stress, clutching their passports and family birth certificates in one hand and their children in the other. Outside the station, there were tearful goodbyes as fighting-age men, banned from leaving Ukraine, stopped and let their families go, unsure if they would ever see them again.

Read more about Ukrainians' gruelling journeys and painful decisions as they pass through Lviv.

British Prime Minister Boris Johnson has rejected calls to ease visa requirements for Ukrainians fleeing the conflict.

He said Britain was a "very generous country", but it wants to maintain checks on who is arriving.

The prime minister added: "I think it's sensible given what's going on in Ukraine to make sure that we have some basic ability to check who is coming in."

Image source, EPA

Ukrainian President Zelensky is calling for more sanctions against Russia.

Speaking at his daily briefing, Zelensky says the continued invasion shows that "Russia has not abandoned its plans against Ukraine" - therefore, he adds, "we need a new sanctions package".

Zelensky calls for "a boycott of Russian exports, in particular the rejection of oil and oil products from Russia".

He adds that these tougher measures "can be called an embargo, or just morality".

Lyse Doucet
Chief International Correspondent, in Kyiv

Image source, Reuters

Humanitarian corridors are now desperately needed.

In the southern port city of Mariupol, encircled by Russian forces, there’s no electricity or running water, people have run out of food, dead bodies lie in the streets.

In other places - including Irpin, just outside the capital - there’s been incessant Russian shelling.

But four of the six proposed routes to safety go to Russia in the east, or to Belarus, its key ally, to the north.

Ukraine has condemned this condition as "completely immoral".

On Day 12 of this invasion, Russian artillery are pounding residential areas of Mykolaiv, another southern city near the Black Sea. In the east, Ukrainian forces say they’ve recaptured the city of Chuhuiv.

In this bloody back and forth, the centre of Kyiv is still eerily quiet - but on the rim of the city, there’s intense fighting and constant explosions.

Anna Holligan
BBC News Hague correspondent

Russia has refused to attend an International Court of Justice (ICJ) hearing where Ukraine is calling for a halt to the invasion.

The Russian ambassador in The Hague, Alexander Shulgin, indicated his government did not intend to participate in the proceedings.

The head judge at the UN's highest court said she regretted the non-appearance of the Russian Federation.

Ukraine's representative Anton Korynevych told the court: "The fact Russian seats are empty speaks volumes, they are not here, they are on the battlefield."

He accused Moscow of defiling the Genocide Convention by using claims of a non-existent genocide as a false pretext to try to justify the invasion.

"Putin lies, Ukrainian citizens die," he said.

Ukraine has asked the ICJ to urgently intervene to ask Russia to immediately suspend its military operation, prevent further civilian casualties and any acts of genocide or rhetoric expressing genocidal intent.

Both Russia and Ukraine are members of the court, and both have signed up to the Genocide Convention.

Yalda Hakim
BBC World News presenter

Until a week ago, this atmospheric building near downtown Lviv was the base for the Centre of Urban History.

But as the rockets began to fall in eastern Ukraine, the people who ran the Centre turned its libraries, offices and kitchens into a temporary home for those fleeing the fighting further east.

Now, mainly women and children have set up stall here, turning their corner of the floor into a temporary home.

Seven-year-old Alicia and her mother Anastasia spent seven days in an underground bunker in Kharkiv.

They've just arrived here with their two rats and cat. Anastasia says Alicia is smiling again - but had witnessed pure horror.

Some families stay for a while, others for just a few days as they re-group, take a breath and continue their journey east towards the border.

One 17-year-old boy who also came from Kharkiv tells us of his relief at getting a Telegram message this morning from his father, a soldier - his message is proof that he is still alive. For now.

Image source, Reuters

Russia's Foreign Minister Sergei Lavrov is expected to meet Ukrainian Foreign Minister Dmytro Kuleba on Thursday in Antalya, Turkey.

The meeting comes as Russia continues its invasion of Ukraine.

Ukraine says rocket attacks have continued on residential areas in several cities, and that the capital Kyiv could face an all-out assault.

A third round of talks is expected to be held between Ukrainian and Russian negotiators in a few hours.

We've now heard they're due to begin at 16:00 Kyiv time (14:00 GMT), according to Ukrainian officials.

Image source, European Pressphoto Agency

Tugan Sokhiev, the prestigious Bolshoi Theatre's chief conductor, has resigned "with immediate effect" after coming under pressure to express his opinion on the Russian invasion of Ukraine.

"First of all I need to say most important thing: I have never supported and I will always be against any conflicts in any shape and form," the Russian conductor said in a Facebook post.

But he resigned without stating his position on the conflict, and also left his post as conductor of Orchestre National du Capitole de Toulouse in France, where he had been pressed to clarify his views.

"Today I am forced to make a choice and choose one of my musical family over the other. I am being asked to choose one cultural tradition over the other," he said.

He said his decision was based on being "forced to face the impossible option of choosing between my beloved Russian and beloved French musicians".

Last week the Munich Philharmonic dismissed Russian chief conductor Valery Gergiev with immediate effect, after he did not respond to calls to condemn the invasion.

Sokhiev added: "I am being asked to choose one cultural tradition over the over. I am being asked to choose one artist over the other.I am being asked to choose one singer over the other.

"I will be soon asked to choose between Tchaikovsky, Stravinsky, Shostakovich and Beethoven, Brahms, Debussy."

He added he could not "bear to witness" how his fellow artists were being "menaced, treated disrespectfully and being victims of so called 'cancel culture'".

Bolshoi general director Vladimir Urin told Tass state news agency he was saddened by the decision.

"I'm very sorry. His departure is a serious problem for the Bolshoi Theatre. It's unclear how the situation will develop from now," he said.

Image source, Reuters

The UK's Ministry of Defence (MoD) has suggested Russia was deliberately targeting Ukraine's communications facilities.

The latest defence intelligence update it published said Moscow was "probably targeting Ukraine's communications infrastructure in order to reduce Ukrainian citizens' access to reliable news and information".

There were reports of a strike on a TV tower in Kharkiv on Sunday, following a similar attack in Kyiv last week.

"Ukrainian internet access is also highly likely being disrupted as a result of collateral damage from Russian strikes on infrastructure," the MoD said.

"Over the past week, internet outages have been reported in Mariupol, Sumy, Kyiv and Kharkiv."

Image source, Reuters

Lithuania's Foreign Minister Gabrielius Landsbergis has called for embargoes on Russian energy sales.

"Energy sources which we import pay for the Russian militaryoperation," Landsbergis said at a joint meeting with US Secretary of State Antony Blinken in Vilnius.

"We cannot pay for oil and gas with the blood of Ukraine."

Italian prime minister Mario Draghi is meeting EU chief Ursula Von der Leyen in Brussels to discuss Italy’s current dependence on Russian energy, and what can be done to diversify Italy's current energy supply.

Italy and Germany are among the European countries who would be most heavily impacted by Russian oil import restrictions.

Katy Austin
Transport correspondent

Image source, Getty Images

We've got some new information on the surge in petrol prices amid Russia's invasion of Ukraine.

Motoring group the AA says the average price of a litre of petrol at UK pumps has hit 155p for the first time - pushing the cost to more than £7 a gallon.

Filling up a car with a 55-litre tank now costs almost £17 more than a year ago, rising from £68.60 to £85.59, the AA says.

On Sunday, petrol reached 155.62p a litre on average, with diesel at 161.28p.

And experts have warned of further price rises to come.

The rise, which has seen oil prices soar to the highest level since July 2008, came after the US said it was discussing a potential ban on Russian supplies with other countries.

Brent crude - the global oil benchmark - rose above $139 a barrel, before easing to around $130 (£99).

James Spencer, managing director of Portland Fuel, warns that "even if we can get extra supplies on to the market, nothing will happen quickly”.

"I'm afraid we are going to see prices in excess of £1.70 to £1.75 a litre."

Image source, EPA

US Secretary of State Antony Blinken, who is on an official visit in Lithuania, says Russia has sought to "undermine Lithuania's democracy and sow polarisation with cyber attacks and disinformation".

He also says the US and his host country are "united in our resolve to stand with Ukraine", as the Russian invasion reaches its 12th day of conflict.

The US was bolstering "our shared defence", he says, so the US and allies are ready "to meet any threat" - including sending a further 7,000 US forces to Europe, and repositioning others "to strengthen Nato's eastern flank".

Secretary Blinken reasserted the US's "sacrosanct" commitment to Nato's Article 5 - "an attack on one is an attack on all" - stressing: "We will defend every inch of Nato territory."

In what the UN has called Europe's fastest growing refugee crisis since World War Two, external, more than 1.7 million civilians have now fled Ukraine because of the Russian invasion.

The European Union says up to four million people may try to leave the country.

So where are all those people going?

Refugees are mostly crossing to neighbouring countries to the west, principally Poland, and also Romania, Slovakia, Hungary and Moldova. Much smaller numbers have gone to Russia and Belarus.

Read more here.

Image source, Getty Images

Indian Prime Minister Narendra Modi has urged Russian President Vladimir Putin to hold direct talks with Ukrainian President Volodymyr Zelensky, according to an Indian government source quoted by Reuters news agency.

"President Putin briefed Prime Minister Modi on the status of negotiations between the Ukrainian and Russian teams," the source said, declining to be named ahead of an official statement.