Biden and Zelensky hold talks on US ramping up Ukraine military support

US President Joe Biden and President Volodymyr Zelensky held talks on Wednesday on ramping up support for the Ukrainian military.

The leaders discussed "additional capabilities" to help the Ukrainian forces, during a telephone call on Wednesday, the White House said in a statement.

Biden pledged $500 million in direct aid to Ukraine, as Kyiv battles against invading Russian forces.

"The leaders discussed... continued efforts by the United States with allies and partners to identify additional capabilities to help the Ukrainian military defend its country," the White House said.

Some 20,000 people are believed to have been killed since the Russian invasion began on 24 February, according to Zelensky, though the number of casualties could not be independently verified.

"Just finished an hour-long conversation," Zelensky tweeted after the call. "Shared assessment of the situation on the battlefield and at the negotiating table.

"Talked about specific defensive support, a new package of enhanced sanctions, macro-financial and humanitarian aid."

Ukraine and Western powers have cast doubt on Russia's pledge to reduce military activity around Chernigiv and the capital Kyiv, made during face-to-face talks in Istanbul on Tuesday.