Over 2,000 Ukrainian children have been abducted amid war with Russia - Zelensky

"We do not know the whereabouts of our children," said Volodymyr Zelensky, speaking at the European Council summit, which he attended virtually.

Zelensky also accused Russian forces of firing on humanitarian aid convoys and targeting women and children in evacuation corridors, reported Anadolu Agency.

Meanwhile, Ukraine's Deputy Prime Minister Iryna Vereshchuk said more than 3,300 people were evacuated from the regions of Kyiv, Donetsk and Zaporizhzhia on Thursday.

However, she said the Ukrainian side was not able to evacuate people living in the besieged city of Mariupol and dozens of buses loaded with humanitarian aid could not enter it.

Russia's war on Ukraine, which began on Feb 24, has been met with international outrage, with the European Union, US and UK among others implementing tough financial sanctions on Moscow.

At least 1,035 civilians have been killed in Ukraine and 1,650 injured, according to estimates by the UN, which cautioned that the true figure is likely far higher.

More than 3.67 million Ukrainians have also fled to neighbouring countries, with millions more displaced inside the country, according to the UN refugee agency.

-- BERNAMA