The United States is sending $625m to Ukraine in additional weaponry, including High Mobility Artillery Rocket System (HIMARS) launchers, in a move that Russia said risks escalating the war.
Zelenskyy has said his forces were making “rapid and powerful” gains and had retaken “dozens” of villages on the two battlefronts.
Biden, who was joined in the call by Vice President Kamala Harris, stressed Washington’s continued support for Kyiv.
Biden “pledged to continue supporting Ukraine as it defends itself from Russian aggression for as long as it takes,” a statement from the White House said.
The military package is the first since Russia announced it was formally annexing four occupied areas of Ukraine following a series of hastily organised referendums that have been condemned as coercive and in breach of international law.
The White House said the arms – to be drawn immediately from existing US military stockpiles – would include four more HIMARS precision rocket launchers, 32 Howitzers with 75,000 rounds of ammunition, 200 Mine-Resistant Ambush Protected (MRAP) vehicles and Claymore anti-personnel mines.
“Recent developments from Russia’s sham referenda and attempted annexation to new revelations of brutality against civilians in Ukrainian territory formerly controlled by Russia only strengthens our resolve,” US Secretary of State Antony Blinken said in a statement.
The advanced weaponry has helped Ukraine in its effort to push back Russian troops amid a rapid offensive that began in early September and swiftly secured control of the Kharkiv region from Russia.
Ukraine is now trying to make further inroads in the south and east before the colder weather arrives and Russia can deploy the 300,000 reservists called up in an unpopular partial mobilisation two weeks ago.
