How can you explain this to your children? - Zelensky

 We can't leave' says hospital employee in Mariupol

Days after a deadly attack on a maternity hospital in Ukraine's southern port city of Mariupol, the city's biggest hospital has been captured and 400 patients and staff are being treated like hostages, officials say.

Regional governor Pavlo Kyrylenko says the regional intensive care hospital, on the western outskirts of Mariupol, was all but destroyed the other day but staff continued to treat patients in the basement.

He has quoted one hospital employee as saying: "The Russians forced 400 people from neighbouring houses to come to our hospital. We can't leave."

Authorities say at least 2,400 civilians have already been killed since Russia's bombardment of the city began. Many of Mariupol's residents are trying to survive in underground shelters.

One human rights group accuses Russian soldiers of threatening to shoot anyone who leaves the hospital, and anyone who has tried to get out has been shot and wounded.

You can read more about the terrible conditions in Mariupol here

Russian TV journalist resigns

A prominent journalist working for a Kremlin-controlled TV station has resigned in the wake of the on-screen protest by Channel One journalist Marina Ovsyannikova.

Vadim Glusker, NTV's Brussels correspondent, has been confirmed to have resigned by the state news agency RIA Novosti.

NTV told RIA Novosti that Glusker stopped working for it "in early March" and that his decision was "to do with health reasons". NTV is Russia's third most popular TV station and is owned by gas giant Gazprom and is firmly pro-Kremlin.

There are also reports that Zhanna Agalakova, Channel One's correspondent in Paris, has resigned - but these have not been confirmed.

Earlier, we brought you reports that a news presenter from NTV had resigned and left the country.

Zelensky says Ukraine should accept it won't join Nato

Volodymyr Zelensky has appeared to suggest the country should accept it won't be able to join the Nato military alliance.

Speaking at a video conference with military officials earlier today, the Ukranian president said, "Ukraine is not a member of Nato. We understand that. We are adequate people."

He continued: "We have heard for years that the doors were open, but we also heard that we could not join. It's a truth and it must be recognised.

"I am glad that our people are beginning to understand this and rely on themselves and our partners who help us."

Before the invasion, Vladimir Putin had demanded that Ukraine was banned from ever joining Nato, as one of the "security guarantees" Moscow was seeking.

97 children have died since Russian invasion of Ukraine - Zelensky

During his address to Canadian MPs, Zelensky says that almost a hundred children have died during Russian's invasion of Ukraine.

Ukraine's president explains the southern besieged city of Mariupol has been left without communication networks and nearly running out of food.

Zelensky adds that 97 children had been reportedly killed since the war began.

Ukrainian President Volodymyr Zelensky is addressing Canada's Parliament now, where he has been greeted by mass applause.

He describes his feelings and those of the Ukrainian people over the past 20 days of Russia's "full-scale aggression". He says: "Imagine at 4am, each of you, you start hearing bomb explosions, severe explosions, can you imagine hearing you, your children, hearing explosions?"

He says cruise missiles are falling on your country, and your children are asking what has happened and you see from the news the infrastructure that has been targeted and that people have died.

The Ukrainian president adds: "How can you explain to your children that full-scale aggression just happened in your country?"

Russia could be planning chemical 'false flag' operation - Stoltenberg

More now from Jens Stoltenberg's press conference.

The Nato chief says that Russia is "making absurd claims about biological labs and chemical weapons" in Ukraine.

"This is just another lie," he says, noting that Russia had originally said it did not plan to invade Ukraine.

"We are concerned that Moscow could stage a 'false flag' operation, possibly including chemical weapons," Stoltenberg says.

A false flag is a political or military action carried out with the intention of blaming an opponent for it.

Stoltenberg says any use of chemical weapons is "absolutely unacceptable".

The US has previously raised similar worries, with the White House saying nations should be on the lookout for Russia "to possibly use chemical or biological weapons in Ukraine, or to create a false flag operation using them".