US President Joe Biden on Monday promised to provide advanced air defense systems to Ukraine after Russian missiles rained down on the capital Kyiv and other cities, the White House said in a statement.
Biden spoke to President Volodymyr Zelensky and "pledged to continue providing Ukraine with the support needed to defend itself, including advanced air defense systems," the statement said.
Russian President Vladimir Putin has threatened more "severe" attacks against Ukraine after the biggest wave of strikes in months killed at least 11 in retaliation for an explosion that damaged a key bridge linking Russia to the Moscow-annexed Crimean peninsula.
After speaking with Biden, Zelensky tweeted that "air defense is currently the number 1 priority in our defense cooperation."
Kyiv said Russian forces had fired more than 80 missiles on cities across the country and that Russia had also used Iranian drones launched from neighbouring Belarus.
Biden "conveyed his condolences to the loved ones of those killed and injured in these senseless attacks," the White House said.
"He also underscored his ongoing engagement with allies and partners to continue imposing costs on Russia (and) holding Russia accountable for its war crimes and atrocities."