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.

Ukraine unleashed more than a hundred drones smuggled deep into Russia in what it called its most damaging attack yet.

Ukraine’s shock drone strike on Russia’s strategic bomber fleet this week has generals and analysts taking a new look at threats to high-value United States aircraft at bases in the homeland and abroad – and the situation is worrisome.