Ukraine has secured the release of 1,456 prisoners of war since Russia invaded on Feb. 24, President Volodymyr Zelenskiy told parliament in an annual address held behind closed doors on Wednesday.
Kyiv and Moscow have held a series of prisoner swaps throughout the war which is now in its eleventh month. Zelenskiy has said the release of prisoners of war is a priority.
Russia is thought to hold thousands of Ukrainian prisoners of war, but the exact figures are not known.
Meanwhile, Russian forces stepped up mortar and artillery attacks on the recently liberated city of Kherson in southern Ukraine on Wednesday, Ukraine's military said, while also exerting constant pressure along front lines in eastern regions of the country.
Russia fired 33 missiles from multiple rocket launchers at civilian targets in Kherson in the 24 hours to early Wednesday, the General Staff of Ukraine's Armed Forces said.
Fighting was particularly intense around the strategic eastern city of Bakhmut in Donetsk province and Svatove, further north in Luhansk province, Britain's defence ministry said.
Ukrainian military analyst Oleh Zhdanov said fighting had intensified with Russia deploying armoured vehicles and tanks.
Russia announced it would ban oil sales to countries that abide by a price cap imposed this month by the West.
Moscow did not consult with OPEC+ on its response to the price cap, Kremlin spokesman Dmitry Peskov said, stating that it was Russia's sovereign right to respond as it sees fit to such "illegal measures"
Russian Prime Minister Mikhail Mishustin said the country's economy, battered by Western sanctions, shrank by more than 2 per cent over the past 11 months.
The Kremlin said peace proposals to end the conflict in Ukraine must take into account what it called "the new reality" of four Ukrainian regions having joined Russia.
Russian President Vladimir Putin said he was open to negotiations and he blamed Ukraine and its Western allies for failing to engage in talks.
Turkey's defence minister, Hulusi Akar, and the head of its National Intelligence Organization (MIT), Hakan Fidan, were in Moscow on Wednesday for talks
