Jeremy Bowen
BBC News, Poland-Ukraine border

There are long lines of coaches and cars at the Medyka border crossing. There are people on foot as well and people who've stopped, maybe because their cars have broken down, camping by the side of the road.

They're all lining up along this straight road, with forest either side, towards the Polish border.

I'd say the queue stretches back about a mile (1.6km) or so, and one thing to remember is this is just one of many border crossings.

This is becoming an enormous refugee crisis. All these people will need shelter, they'll need food, there are many children - it's tough for them.

Nada Tawfik
BBC News, New York

President of the UN General Assembly Abdulla Shahid was the first to speak. He has said the assembly represents the collective conscience of humanity and its strength is rooted in its moral authority.

Remember, all 193 nations have a say in the General Assembly, unlike the Security Council which has five permanent, veto-wielding members and 10 non-permanent members who hold two-year terms.

Shahid has urged all nations to demonstrate moral courage and to use the debate over the next few days not to "whip up war rhetoric, but to give peace a chance".

He also reminded the 193 members of the UN that in 1946 the League of Nations dissolved because of its failure to provide a mechanism for the enforcement of international collective security.

He said the UN was founded to take effective collective measures for the prevention and removal of threats to peace.

Nada Tawfik
BBC News, New York

This is only the 11th emergency special session of the UN General Assembly since the first in 1956. The rare nature of this meeting underscores the huge concern surrounding this crisis.

The morning session will kick off with speeches by the president of the General Assembly (GA) and the secretary general, followed by more than 100 members of the UN over the next few days.

Diplomats expect a vote on a draft resolution – which is still being negotiated – on Wednesday.

The UN Security Council called this session after it was prevented from acting when Russia vetoed a US draft resolution on Friday, which deplored its aggression against Ukraine and demanded the immediate withdrawal of all of its troops from the country.

The draft GA resolution is expected to pass because no nation holds a veto in this chamber, but it is not legally binding like security council resolutions.

Fifa is in advanced talks over the full suspension of Russia until further notice, according to BBC sports editor Dan Roan.

The global football governing body is understood to be working closely with its European counterpart Uefa and an announcement is expected later today.

It would mean Russia would not be able to play at the women's Euro 2022 in England in the summer and Poland will get a bye in the World Cup qualifier play-off next month - a match that Poland's FA has said it will boycott.

Iceland has also said it will refuse to play against Russia in June, and the International Olympic Committee has recommended that athletes from Russia and Belarus be banned from competitions.

We have more about what Guterres is expected to tell the UN as it meets to discuss the situation in Ukraine.

The secretary general will say the world is facing a tragedy for Ukraine, but also a major regional crisis with "potentially disastrous" implications.

He is set to to describe the decision to put Russian nuclear forces on high alert on Sunday as "a chilling development" and that the idea of a nuclear conflict was "simply inconceivable".

In remarks to the UN General Assembly's special session on Ukraine, which is meeting in New York, UN Secretary General António Guterres is expected to call for the fighting there to stop.

He is also due to say that the UN has "credible accounts" Russian strikes are hitting residential buildings, critical civilian infrastructure and other non-military targets.

Guterres is expected to say that the sovereignty, independence and territorial integrity of Ukraine, within its internationally recognised borders, must be respected.

Lord Lebedev, the Russian-born magnate who owns London's Evening Standard newspaper, has urged Vladimir Putin to stop the invasion of Ukraine.

Lebedev has published an open letter to the Russian leader on today's front page.

Lebedev, who is a long-term friend of UK PM Boris Johnson and sits in the House of Lords, says: "I plead with you to use today's negotiations to bring this terrible conflict in Ukraine to an end."

The letter appears alongside a photograph of a paramedic performing CPR on a six-year-old girl who was injured after shells struck her apartment block in Mariupol, Ukraine, on Sunday.

"As a Russian citizen I plead with you to stop Russians killing their Ukrainian brothers and sisters. As a British citizen I ask you to save Europe from war,” he says.

Image source, Evening Standard

How are people in shelters getting food and water?published at 14:51 Greenwich Mean Time 28 February 2022

14:51 GMT 28 February 2022

Lyse Doucet
Chief International Correspondent, Kyiv

Arlene in Salem, in the US state of Oregon, asks: "How are the people in shelters getting food, water, and sanitation needs met? Is there an International Red Cross in action and/or do the hospitals still attend to patients and the wounded? Is there any food available in Kyiv at this time?"

When the curfew lifts, and air-raid sirens go silent, people nervously rush to the shops - if the shops are open, and the shelves still have supplies.

We've heard from metro stations-turned-refuges that people are coming together to help each other. But when curfews remain in force for 36 hours, food and water starts running short. Some residents have been moving into local hotels.

They're also doing what they can to keep people fed. There's a great community spirit - everyone is pitching in, including international and local organisations. But the concern is if this goes on too long that even finding food will be hard.

Image source, Reuters

What's stopping Russia from conquering Ukraine?published at 14:43 Greenwich Mean Time 28 February 2022

14:43 GMT 28 February 2022

Lyse Doucet
Chief International Correspondent

John from the US asks: "Is the Russian military holding back their full ability, or are the logistics-based issues they’re having actually preventing them from conquering Ukraine?"

Sitting in Kyiv, many thought that the sight of Russian troops in the heart of this capital was just a matter of time - they counted it in hours. But Ukrainian forces are resisting, and Russian forces are said to still be about 30km from the city centre.

With every day, more of the combat troops and heavy weaponry marshalled along Ukraine’s borders move forward in all directions, but not as fast or as far as many expected.

It’s hard to say whether or not it is not “going according to plan” because no-one knows what President’s Putin plan is. But there’ve been reports of Russian convoys running out of fuel, Russian soldiers losing the will to fight, and Ukrainians fighting back - both soldiers and civilians, some armed only with the force of patriotism.

There’s also been heavy street-to-street fighting in areas including the second largest city of Kharkiv. And Russian troops have been advancing and attacking - against the north-eastern city of Chernihiv and the southern city of Maripul, among many others.

Imogen Foulkes
BBC News, Geneva

After some soul-searching, neutral Switzerland will adopt all EU sanctions against Russia.

There will be no exceptions: five oligarchs have already been banned from entering Switzerland, the bank accounts of all 336 people on the EU’s list, including Vladimir Putin and Sergei Lavrov, will be frozen with immediate effect.

Swiss banks are believed to hold billions of dollars in Russian funds.

The country's air space is closed to Russian aircraft, while Swiss airlines have cancelled their flights to Russia.

Make no mistake, this is a huge step for Switzerland, which has often agonised over what being neutral actually means.

Today Swiss President Ignazio Cassis made it clear: the attack on Ukraine was an unacceptable attack on freedom and democracy, "playing into the hands of aggression is not neutral", neither is standing by while the Geneva Conventions, which Switzerland is home to, are "trampled underfoot".

The International Olympic Committee has recommended to international sports federations that athletes from Russia and Belarus will be banned from competitions in light of the ongoing invasion of Ukraine.

In a statement issued on Monday, external, the organisation's executive board wrote that in cases where it proves impossible to prevent athletes from taking part, they should be prevented from doing so under the names Russia or Belarus.

"No national symbols, colours, flags or anthems should be displayed," it added.

How will promised supplies for Ukraine reach the front line?published at 14:24 Greenwich Mean Time 28 February 2022

14:24 GMT 28 February 2022

Mark Lowen
BBC News, Ukraine-Poland border

Andy Sheridan asks via Twitter: "How will the promised essential supplies and weaponry make it to the front lines given the superiority of Russian air power?"

It’s all going in through Ukraine’s western border - principally Poland. Military flights have arrived here from as far afield as the US and Canada and it’s then largely being driven across the border, due in part to the threat from Russian air power.

Ukrainian airspace remains closed to civilian flights. Some military aid is arriving here in Poland by train too, including from the Czech Republic.

It’s an enormous logistical operation to resupply Ukraine’s military.

Image source, EPA

What would happen if Russia takes control of Ukraine?published at 14:18 Greenwich Mean Time 28 February 2022

14:18 GMT 28 February 2022

Lyse Doucet
Chief International Correspondent

Image source, Reuters

Nhlanhla in South Africa asks: "If Russia manages to take over Ukraine, what's next?

That is an existential question for Ukraine, a defining and dangerous moment for the world.

First, Russian forces would have to seize far larger swathes of territory of Europe’s second-largest country, including the capital Kyiv, a city of nearly three million people known to be resolutely pro-European and pro-Nato.

History tells us military coups and invasions have succeeded by taking over television stations and presidential palaces. That’s not going to be enough.

There would be a ferocious counter-attack, and a Ukrainian insurgency would quickly rise. Support would pour in from many directions, many sources, and of many kinds.

It’s hard to imagine that takeover would survive. It would go down in history as the darkest of dark hours.

Is the UK in any danger?published at 14:13 Greenwich Mean Time 28 February 2022

14:13 GMT 28 February 2022

Lyse Doucet
Chief International Correspondent

Becky in Weymouth, in the UK, asks about the risks of the conflict spreading. She particularly worries whether President Putin could decide to attack the UK.

I am so sorry that you have to ask this terrible and terrifying question. I would want to answer, no chance.

These are unpredictable, unfathomable times but I would still like to believe the answer is no – no to the bombing of Britain or any other country. And a hope that the bombing of Ukraine is swiftly brought to an end.

As we are answering your questions, talks continue on the Belarusian border between Russian and Ukrainian officials. It's the first time they have met since Russia invaded, but hopes of a breakthrough are not high.

Ahead of the talks, Ukraine said it wanted a ceasefire and Russian withdrawal, while the Kremlin said it would not announce its position. Russia's negotiators have talked of striking a deal that's in the interests of both sides.

The Ukraine delegation includes Defence Minister Oleksiy Reznikov and Deputy Foreign Minister Mykola Tochytskyi. Russian Deputy Defence Minister Alexander Fomin, Putin's adviser Vladimir Medinsky and Russian Ambassador to Belarus Boris Gryzlov are also among those there.

How many foreign fighters have travelled to Ukraine?published at 14:02 Greenwich Mean Time 28 February 2022

14:02 GMT 28 February 2022

Mark Lowen
BBC News, Ukraine-Poland border

George Menachery in Kerala, India, asks: "How many foreign fighters have joined Ukraine in response to its president's call?"

It's unclear for now. Ukraine’s president has urged foreigners to join what he called an “international brigade” but we don’t know the numbers of those who’ve responded.

Ukraine’s embassy in Israel issued a Facebook post appealing for Israelis to travel to Ukraine to fight, but it was later deleted.

Has any other country sent troops to help Ukraine?published at 13:56 Greenwich Mean Time 28 February 2022

13:56 GMT 28 February 2022

Mark Lowen
BBC News, Ukraine-Poland border

Thomas Ogren in San Luis in the US asks: "Has any country in the entire world actually sent any of their troops to help Ukraine?"

Not officially. No Nato member wants to risk a direct military confrontation between its troops and those of Russia.

President Biden, for example, has repeatedly stated that there will be no American troops fighting in Ukraine.

But we don’t know if there are foreigners there, covertly working with the Ukrainian army, particularly in the light of the calls from Ukraine’s president for foreigners to go and help.

Downing Street has issued a warning to businesses still working in Russia, saying they should "think very carefully if they are still continuing to do anything that props up the Putin regime".

The UK prime minister's official spokesman also downplayed suggestions that the government supported British citizens helping Ukrainians fight Russia, saying that "we fully recognise the strength of feeling" but that the advice is not to travel to Ukraine.

It comes after the Kremlin appeared to blame remarks by Foreign Secretary Liz Truss - who said that other countries would feel threatened by Moscow if Putin wasn't stopped in Ukraine which could end up in a Nato conflict - for its decision to put its nuclear deterrence on "special alert".

Boris Johnson will travel to Poland and Estonia on Tuesday for meetings with other national leaders and the Nato secretary general, No 10 said.

Will Nato send troops to help Ukraine?published at 13:41 Greenwich Mean Time 28 February 2022

13:41 GMT 28 February 2022

Lyse Doucet
Chief International Correspondent, Kyiv

Image source, Reuters

Tim Mepham from Brighton asks: "At what point will the countries of Nato agree enough is enough and put boots on the ground to support Ukraine?"

Nato countries and allies are watching Russia’s every move, warning that their defensive military alliance will do everything to defend "every inch" of their territory.

They've sent weapons and ammunition to Ukraine, and trained Ukrainian soldiers in recent years - indeed right up to the Russian invasion.

But they've repeatedly said there will be no Nato "boots on the ground" because Ukraine is not a Nato member.

However, this changes if Russia moves beyond Ukraine into a Nato country.

Article 5 of Nato’s constitution states that "an attack against one ally is considered an attack against all allies".

If that happens, the world moves into uncharted territory and there’s a dangerous possibility of a Nato-Russia confrontation.

A quick news update for you now as Russia has announced it is banning flights from airlines in 36 countries, including the UK, Germany, Spain, Italy and Canada.

It follows a decision by the EU to ban "Russian-owned, Russian-registered or Russian-controlled aircraft" from its airspace.

The UK also banned Aeroflot flights from landing in Britain, prompting Russia to announce an earlier retaliatory ban on British airlines.