Russia launched its biggest aerial attack against Ukraine overnight, a Ukrainian official said Sunday, part of an escalating bombing campaign that has further dashed hopes for a breakthrough in efforts to end the 3-year-old war.

Russia fired a total of 537 aerial weapons at Ukraine, including 477 drones and decoys and 60 missiles, Ukraine's air force said. Of these, 249 were shot down and 226 were lost, likely having been electronically jammed.

Yuriy Ihnat, head of communications for Ukraine's air force, told the Associated Press that the overnight onslaught was the most massive air strike on the country, taking into account both drones and various types of missiles. The attack targeted regions across Ukraine, including western Ukraine, far from the frontline.