Russia fired its largest missile and drone attack on Ukraine in more than three years of war, Kyiv said Wednesday after strikes that mainly targeted areas furthest from the front line.

The attack comes just after US Donald Trump said he would increase weapons deliveries to Ukraine -- reversing an earlier US policy announcement -- and accused his Russian counterpart Vladimir Putin of talking "bullshit" on Ukraine.

AFP journalists in Kyiv heard explosions ringing out and drones buzzing over the capital after air raid sirens sounded.

The latest strike beat a previous Russian record of 550 drones and missiles set last week.

The Ukrainian air force said that Russia had attacked with 728 drones and 13 missiles, adding that its air defence systems intercepted 711 drones and that at least seven missiles were destroyed.

"This is a telling attack -- and it comes precisely at a time when so many efforts have been made to achieve peace, to establish a ceasefire, and yet only Russia continues to rebuff them all," Ukrainian President Volodymyr Zelensky wrote on social media.

He called for allies to step up sanctions on Russia, particularly targeting its energy sector, an important revenue stream for the Russian war chest.

"Our partners know how to apply pressure in a way that will force Russia to think about ending the war, not launching new strikes," Zelensky added.

The mayor of the western city of Lutsk, Igor Polishchuk, said fires had broken out at an "enterprise," and said no one had been reported killed or wounded.

The strike comes just after the United States U-turned on an announcement that it would reduce some weapons supplies to Ukraine.

"It is quite telling that Russia carried out this attack just as the United States publicly announced that it would supply us with weapons," the Ukrainian president's chief of staff, Andriy Yermak, wrote on social media.

Several rounds of direct talks between Russian and Ukrainian delegations saw an increase in prisoner exchanges but made no progress on securing a ceasefire, proposed by the United States and Ukraine.

The Kremlin has since said it sees no diplomatic path from the conflict, launched by the Kremlin in February 2022, and vowed to pursue its war aims -- conquering Ukraine and removing its political leadership.

Ukraine has also sought to increase its strike potential inside Russia, and Moscow's defence ministry said Wednesday its air defence units had downed 86 unmanned aerial vehicles, mainly over western regions of the country.