Ukrainian President Volodymyr Zelensky has ruled out liberating the besieged port city of Mariupol, occupied by Russian troops, for the time being.
"Ukraine does not have enough heavy weapons to liberate Mariupol by military means," Zelensky told a news conference with Canadian Prime Minister Justin Trudeau, who is Kiev for a solidarity visit.
Though it had been possible to get civilians out of the besieged Azovstal steelworks through diplomatic channels, evacuation for the remaining Ukrainian soldiers in the plant is proving difficult, he said.
"The Russian soldiers, the Russian army, the military leadership and the political leadership of the Russian Federation do not want to let our soldiers go," Zelensky said.
The south-eastern Ukrainian port city of Mariupol has been largely under Russian control for several weeks. At the weekend, the last trapped civilians were evacuated from the city's steel plant.
However, hundreds of Ukrainian fighters are said to still be holed up in the plant's bunkers and do not plan to surrender.
