ITV News Europe Editor James Mates reports on the day's key developments as the first humanitarian corridor of the war opens
The evacuation of Ukrainians from areas under Russian attack have begun in at least one city, after a safe route was opened on Tuesday.
Buses, packed with people fleeing shelling in the eastern city of Sumy, were seen processing along a snowy road out of the city.
Video posted by the Ukrainian state communications agency showed people with bags boarding buses, but it was not clear how long the effort would last.
Ukrainian President Volodymyr Zelenskyy, who gave a rallying speech to British MPs on Tuesday, said evacuation buses had been sent to Mariupol too. He added that there was no firm agreement on the route, so "Russian troops can simply shoot on this transport on the way".
In full: Ukraine's President Zelenskyy addresses Britain's MPs in the House of Commons
Despite promises of safe passage and there being some successful evacuations, Russian forces have reportedly disrupted humanitarian corridors established in Mariupol and Sumy.
This is the third successive day Russian soldiers have breached their own ceasefire agreements, according to the Ministry of Defence (MoD), which cited reports that shelling and small-arms fire erupted throughout Tuesday.
"Those civilians forced to remain continue to suffer from shortages of power, food and water exacerbated by heavy Russian shelling," the MoD said.
It comes as the latest UN estimate put the civilian death toll in Ukraine at 474, but the human rights office warned the true figure would be much higher.
Multiple attempts have been made to allow civilians safe passage out of Ukrainian cities under attack - but Russian forces have reportedly broken every ceasefire, with claims forces have even targeted those trying to flee.
The humanitarian corridor out of Sumy was one of five promised by the Russians to offer civilians a way to escape the fighting.
"The Ukrainian city of Sumy was given a green corridor, the first stage of evacuation began," the agency tweeted. Sumy is just 50 kilometres (30 miles) from the Russian border.
Russian plans for evacuation corridors were met with scepticism on Tuesday, following repeated broken ceasefires by the invading forces.
In the capital Kyiv, a steady rain of shells and rockets had fallen in suburban areas, with the mayor reporting heavy artillery fire.
"We can’t even gather up the bodies because the shelling from heavy weapons doesn’t stop day or night," Mayor Anatol Fedoruk said.
Our Global Security Editor Rohit Kachroo along with the ITV News teams witnessed desperate scenes, as people tried to escape fighting near the capital.
Ukrainians fleeing Irpin, a besieged city near Kyiv, described the situation as "hell".
In one of the most desperate cities, the encircled southern port of Mariupol, an estimated 200,000 people — nearly half the population of 430,000 — were hoping to flee.
Buses emblazoned with red cross symbols carrying water, basic food staples, and medicines moved toward the besieged port on Tuesday.
Deputy Mayor Sergey Orlov told ITV News the city was under "continuous shelling".
Mariupol's Deputy Mayor Sergey Orlov tells ITV News about the situation the city faces
Mariupol has been left short on water, food and power, and mobile phone networks are down. Stores have been looted as residents search for essential goods.
Hospitals in the city are facing severe shortages of antibiotics and painkillers, and doctors performed some emergency procedures without them.
Ukraine's Foreign Affairs minister on Tuesday said a child in the city had died of dehydration, writing: "War crimes are part of Russia’s deliberate strategy."
The opening of a safe corridor comes as the economic pressure on Moscow continues to increase. On Tuesday, the UK and US announced they would ban the import of Russian oil and oil products by the end of 2022.
Mr Biden went further than the UK by banning all Russian oil, gas and energy - a move he said was "targeting the main artery of Russia's economy".
ITV News US Correspondent Emma Murphy explains how President Biden hopes the new sanctions will hit Russia
In a historic address to UK MPs in the House of Commons, President Zelenskyy called for yet more sanctions and repeated his plea for a no-fly zone over his country.
He also invoked British wartime leader Winston Churchill, vowing Ukraine "will fight to the end".
Meanwhile, in a show of solidarity, Poland’s government said it will hand over all its MIG-29 fighter jets to the US, who will then transfer them to Ukraine.
Correspondent Dan Rivers looks at whether extra firepower from Poland will make a big difference to Ukraine
The numbers of people fleeing Ukraine reached two million on Tuesday, according to the United Nations.
The figure is the fastest exodus Europe has seen since World War II.
Michelle Bachelet, the UN high commissioner for human rights, is pressing for all civilians trapped by fighting in Ukraine to be allowed to leave safely. She said she is "deeply concerned about civilians trapped in active hostilities in numerous areas."
Ms Bachelet also told the UN Human Rights Council that her office has received reports of pro-Ukrainian activists being arbitrarily detained in areas of eastern Ukraine that have recently come "under the control of armed groups."
For analysis - listen to our podcast: What You Need To Know
She said there have been reports of beatings of people considered pro-Russian in government-controlled areas.
At The Hague in Netherlands, Ukraine pleaded with the International Court of Justice to order a halt to Russia’s invasion, saying Moscow is committing widespread war crimes.
Russia snubbed the court proceedings, leaving its seats in the Great Hall of Justice empty.