Russia has hit Ukraine's second-largest city, Kharkiv, with a massive drone and bomber attack, killing four people and injuring nearly 60, officials say. Two people were also killed in Russian strikes on Kherson, in southern Ukraine, local authorities said.

Russia hit Ukraine with a barrage of missiles and drones days after Kyiv's planned drone attack in Russian territory. The attack comes a day after President Trump voiced frustration on the stalled peace talks between the countries.

President Trump said the Russian leader Vladimir Putin had warned that he would retaliate for a covert Ukrainian attack in Russia last weekend that destroyed dozens of Russian bombers.