If you're just joining us now, here's a quick look at what you need to know to bring you up to speed:

• Ukraine has refused to surrender Mariupol, rejecting a demand from Russia to give up the city by the deadline of 05:00 Moscow time (02:00 GMT)
• Russia had offered to set up humanitarian corridors so residents could leave in exchange for the city
• About 300,000 people remain trapped with little if any food, water and power in the city which has been incessantly bombed for the past two weeks.
• Russia has struck several civilian shelters, schools, a hospital and a theatre. Ukraine has said the Mariupol attacks are war crimes that will go down in history
• There was a 24-hour lull in shelling across most cities on Sunday. But in Kyiv, the capital saw strikes which killed at least four people.

• Ukrainian President Zelensky has also criticised Israel for its reluctance to send its missile defence technology to Ukraine
• In a speech to the Israeli parliament, he said: “Everybody knows your missile defence systems are the best… you can definitely help our people.

With that, this is Boer Deng in Washington DC signing off and handing over to my colleagues Yvette Tan and Frances Mao in Singapore.

Sunday night's live coverage was also brought to you by Leo Sands, Bernd Debusmann, George Wright, Joshua Cheetham and Laurence Peter at BBC locations around the world.

There has been an ammonia leak at a chemicals plant in the besieged northeastern city of Sumy, the regional governor Dmytro Zhyvytskyy has said.

Zhyvytskyy warned those within a five-kilometre radius of the Sumykhimprom plant should leave the area as the gas is hazardous.

The official did not say what had caused the leak in the 04:30 local time (02:30 GMT) post on his Telegram channel.

Image source, State Emergency Services of Ukraine

More now on reports of shelling on Sunday that targeted residential houses and a shopping district in Kyiv.

Emergency services in the capital say that at least four people have been killed in the attack, up from a previous death toll of one.

In a post on his Telegram channel, the capital's mayor Vitali Klitschko said that rescue workers are still putting out a large fire at the site of the attack.

Images released by emergency services show a rescue operation underway at a Kyiv shopping mall, but the BBC has not been able to verify the reports on the ground.

Image source, Getty Images

US President Joe Biden will visit Poland on Friday following meetings with Nato and EU allies, the White House announced.

In Poland, Biden will meet with President Andrzej Duda in Warsaw to discuss the humanitarian response to the war in Ukraine.

"The President will discuss how the United States, alongside our Allies and partners, is responding to the humanitarian and human rights crisis that Russia’s unjustified and unprovoked war on Ukraine has created," the White House said.

On Monday, Biden is due to hold a call with French President Emmanuel Macron, German Chancellor Olaf Scholz, Italian Prime Minister Mario Draghi, and UK PM Boris Johnson.

On Wednesday, he will travel to Brussels to attend summits at Nato and the European Council, as well as a G7 meeting. However, he has no plans to travel to Ukraine during his trip, the White House spokeswoman said.

Image source, Getty Images

US Deputy National Security Adviser Daleep Singh has said that the US could still expand sanctions and reach "the commanding heights" of Russia's economy.

In an interview with CBS' 60 Minutes, Singh said that Russia is already "looking into an economic abyss" and is "on a fast track to a 1980s-style Soviet living standards".

Despite the economic toll caused sanctions already enacted, Singh said that they could still be broadened and applied to other targets, including more banks and "sectors that we haven't touched".

"It's mostly about oil and gas, but there are other sectors too," he said. "I don't want to specify them, but I think Putin would know what those are."

Singh noted that projections suggest that Russia's economy will be half the size that it was before the invasion of Ukraine.

"We take no pride in the suffering of the Russian people," he said. "This is Putin's war. These are Putin's sanctions. And this is Putin's hardship he's putting on the Russian people."

Image source, Getty Images

If you're just joining us, here are all the latest developments from Ukraine:

• Ukraine has ignored a deadline given by Russia for forces to surrender the city of Mariupol by 05:00 Moscow time, 04:00 local time.

• Moscow had said that it would open up humanitarian corridors if Ukrainian officials agreed to lay down arms. However, the Ukrainians have rejected the demand and vowed to continue fighting.

• This comes as Mariupol officials earlier said that Russia had attacked an art school in the city, where about 400 people were sheltering

• Heavy shelling of a residential area and shopping district in Kyiv has left at least one person dead, according to Mayor Vitali Klitschko.

• On Sunday, Ukrainian President Volodymr Zelensky spoke to the Israeli parliament to rally support

•Ukrainian authorities say over 7,000 people were evacuated through humanitarian corridors on Sunday.

Survivors from the bombardment of Mariupol have received treatment in the nearby city of Zaporizhzhia where some of the youngest victims of the war are bearing the physical and mental scars of the conflict.

At the hospital the BBC's Wyre Davies heard from one doctor who said that he hated Russia for carrying out the invasion.

Image source, Reuters

Moscow's humanitarian promises cannot be trusted, according to Pyotr Andryushenko, an adviser to the mayor of Mariupol, and the city is not going to stop defending itself, he said.

"We will fight until the last of our soldiers," Andryushenko told the BBC.

Andryushenko repeated unconfirmed claims made by other Mariupol officials in recent days that Russian forces have been forcibly evacuating some of its residents to Russia.

"When they [Russian forces] say about humanitarian corridors, what do they really do? They really force evacuate our people to Russia," he said.

The BBC has not been able to verify these accusations.

Image source, Getty Images

The Chinese ambassador to the United States says that China will not send weapons and ammunition to support Russia’s war in Ukraine and that Beijing would “do everything to de-escalate the crisis”.

Qin Gang's comments come after US President Joe Biden warned his Chinese counterpart Xi Jinping on Friday that there would be "consequences" if Beijing provided material support to Moscow.

Beijing denied reports last week that it was open to providing Moscow with armaments as "disinformation", but China has been reluctant to rebuke Russia for its invasion.

Speaking to US broadcaster CBS, Gang complained that public condemnation by the West "doesn't help" and that "good diplomacy" was needed.

The United Nations' refugee agency (UNHCR) says 10 million Ukrainians have now fled their homes because of the war - almost a quarter of the population.

It described the speed and scale of the displacement as "unprecedented" in recent decades.

Nearly 3.5 million people have left the country since Russia invaded last month. Almost twice that number have sought refuge in safer parts of Ukraine.

Image source, Getty Images

Image source, Getty Images

Image source, Getty Images

Image source, Getty Images

Image source, Reuters

Slovenian Prime Minister Janez Janša has announced that previously evacuated embassy staff will be returning to Kyiv.

In a tweet on Sunday, Janša said that the returning diplomats are volunteers.

"We are working to make the [EU] do the same," he added. "[Ukraine] needs diplomatic support".

On 15 March, Janša, along with Czech Prime Minister Petr Fiala and Polish Prime Minister Mateusz Morawiecki, visited Kyiv and met with Ukrainian President Volodymyr Zelensky.

Following the meeting - the first by Western leaders since Russia invaded Ukraine on 24 February - the Czech leader told Ukrainians that they were "not alone".

Read more about their visit here.

Image source, Getty Images

Ukrainian President Volodymyr Zelensky has said that he believes a failure to negotiate the end of Russia's invasion will mean "a third world war".

Speaking to CNN on Sunday, Zelensky said he is ready to deal directly with Russian President Vladimir Putin, adding that he believes that negotiations are the only way to end the fighting.

"I think that we have to use any format, any chance in order to have a possibility of negotiating," he said.

However, Zelensky said that he reject any agreement that would require Ukraine to recognise Russian-sponsored separatist regions as independent.

The Ukrainian president said he believed that if his country were a Nato member, "a war wouldn't have started".

"If Nato members are ready to see us in the alliance, then do it immediately," he said. "Because people are dying on a daily basis".

Image source, Getty Images

Russia's Ministry of Defence has called on the embattled city of Mariupol to surrender by 05:00 local time (03:00 GMT) on Monday morning - a proposal that Ukraine has rejected.

According to Russia's state-owned Ria Novosti news agency, the ministry has said that it will open humanitarian corridors to allow residents to leave by 10:00 local time (08:00 GMT) if it receives a written response to the proposal.

Colonel-General Mikhail Mizintsev, the head of Russia's National Center for Defense Management, was quoted by Ria Novosti as saying that local officials would face a "military tribunal" if they don't agree to the surrender terms.

Early on Monday, Ukrainian Deputy Prime Minister Iryna Vereshchuk said that there can be "no question" of surrender.

"We have already informed the Russian side about this," she was quoted as saying by Ukrainska Pravda.

On Saturday, Mariupol's City Council accused Russia of illegally taking "several thousand" residents to Russia by force.

The Russian bombardment of Mariupol has led to some of the greatest destruction ever seen in the city.

As the city continues to face shelling, thousands are hiding in shelters and the dead have had to be buried in mass graves.

The BBC's Ukrainian service shared drone footage of some of what the city looks like this weekend.

More now on reported shelling of residential houses and a shopping district in Kyiv late on Sunday.

Mayor Vitali Klitschko says one person has been killed in Podilskyi district.

Rescuers are extinguishing a large fire in one of the shopping centres, he wrote on social media.

Meanwhile, the Ukrainian emergency services (SES) released images of rescue and firefighting in the area.

Eyewitnesses spoke of several explosions.

Identifying information regarding the alleged victim who was killed is being investigated, the emergency services said.

Image source, State Emergency Service of Ukraine

The UK Defence Ministry says that Russian forces advancing from Crimea are still attempting to circumvent Mykolaiv as they look to drive west towards Odesa.

But it says these forces have made little progress over the past week.

"The blockade of the Ukrainian coast is likely to exacerbate the humanitarian situation in Ukraine, preventing vital supplies reaching the Ukrainian population," the ministry said in a Twitter post.

Image source, Getty Images

A Russian journalist who was arrested after protesting the war in Ukraine on live TV says she hoped to "expose propaganda" being broadcast to her fellow citizens.

Marina Ovsyannikova, an editor at state-controlled Channel 1, was detained after she ran on to the set last week holding a sign saying "no war".

Speaking to US broadcaster ABC's "This Week" programme on Sunday, Ovsyannikova, said that she felt her employer was spreading "lies" about Russia's invasion of Ukraine.

"I could see what in reality was happening in Ukraine," she said. "What we showed on our programmes was very different from what was going on in reality".

According to Ovsyannikova, she first considered joining street protests in Russia, but decided that her protest on television would be more "meaningful" and have a greater impact.

"I could show to the Russian people that this is just propaganda, expose this propaganda for what it is," she said.

She was released from custody following a 14-hour interrogation and fined 30,000 rouble (£172; $227).

Residential houses and a shopping district were shelled in Kyiv late on Sunday, mayor Vitali Klitschko said.

"Several explosions in the capital's Podilskyi district," Klitschko said on his Telegram channel.

"According to the information we have at the moment, several homes and one of the shopping centres [were hit]. Rescue teams, medics and the police are already on site."

Image source, Reuters

A Greek diplomat who was caught in the Russian bombardment of Mariupol says the besieged city's devastation is like that of Guernica, Stalingrad, Grozny and Aleppo.

Manolis Androulakis, Greece's Consul General in Mariupol, flew back to Athens on Tuesday after organising several successful evacuations of Greek nationals and ethnic Greeks.

He called on people to "unite their voices to ask for a truce, a ceasefire".

Androulakis has been hailed as a hero in Greece for staying in Mariupol during the bombardment. He said Mariupol will be remembered as a city "completely destroyed by the war".

Ukraine's President Volodymyr Zelensky describes the shelling of Mariupol as a war crime.

Androulakis said that "right now, civilians are hit blindly and helplessly" in the port city.

“In 24 hours, which made my efforts even harder, all the infrastructure was destroyed, everything was bombed, electricity, water, communications.”

Image source, Getty Images

A total of 7,295 people were evacuated from Ukrainian cities through humanitarian corridors on Sunday, Ukraine's Deputy Prime Minister Iryna Vereshchuk said.

Four out of seven planned safe routes are working, she said.

Of the total, 3,985 people were evacuated from the besieged city of Mariupol to Zaporizhzhia, she said, adding that the government plans to send about 50 buses to pick up evacuees from Mariupol on Monday.