There are reports that the city of Kharkiv in Ukraine has been hit by a huge Russian bombardment, on the 5th day of the invasion.
The Ukrainian interior minister is claiming dozens of people have been killed in the rocket strikes, and hundreds more wounded.
It's also understood that shelling has intensified in the city of Donetsk.
On the diplomatic front, talks are under way between officials from both sides.
Ukraine wants an immediate ceasefire and Russian troops to leave.
Sky's security and defence editor, Deborah Haynes, is in Ukraine and says videos and photos from Kharkiv are beginning to emerge:
BREAKING: Dozens of people have been killed in Russian rocket strikes on the Ukrainian city of Kharkiv, Ukraine's interior ministry adviser Anton Herashchenko has said.
Sky's @haynesdeborah has the latesthttps://t.co/X3flQUBL0r
📺 Sky 501, Virgin 602, Freeview 233 and YouTube pic.twitter.com/5a53ezxavG— Sky News (@SkyNews) February 28, 2022
Oxygen Supplies
World health officials warn oxygen levels are running 'dangerously' low in Ukraine, as they call for the 'safe passage' of medical supplies.
They say trucks aren't able to get to hospitals, including in the capital Kyiv.
British intelligence suggests Russian troops are around 30 kilometres from the city centre.
However, there's been shelling and strikes on the area.
Not A Picnic
Ukraine's president has asked foreign nationals to consider joining their fight.
There are suggestions from the Kremlin that might be why the Russian president's put his nuclear weapons on 'high alert'.
Akos Horvath has been to the Ukrainian embassy in London to sign up to their armed forces.
He was asked if he has any military experience.
"Not really."
"I know how to fire a gun."
"I know where I'm going will not be a picnic."
"This is war, I do have a chance to die and yes I've been thinking about it."
More than 500,000 refugees have now fled from Ukraine into neighbouring countries.
— Filippo Grandi (@FilippoGrandi) February 28, 2022
Nuclear Weapons
The Taoiseach has said he doesn't want to contemplate the use of nuclear weapons by Russia.
Micheál Martin said Vladimir Putin has been reckless and irresponsible to suggest he may take the nuclear option.
It comes as talks between Ukraine and Russia are underway near the Ukrainian border with Belarus.
The Ukrainian Ministry of the Interior has said dozens of people have been killed in shelling in Kharkiv today.
Taoiseach Micheál Martin said the EU will strongly support Ukraine and condemned the Russia threat of nuclear weapons:
"I don't even want to contemplate that."
"I think its extremely reckless and irresponsible of Vladimir Putin to threaten that."
More than 500,000 refugees have now fled from Ukraine into neighbouring countries.
— Filippo Grandi (@FilippoGrandi) February 28, 2022
Donations
Revolut also is not charging Ukrainian customers fees when they want to send money to other banks in the country.