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, Associated Press reported.

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.

The onslaught was “the most massive airstrike” on the country since the beginning of Russia’s full-scale invasion in February 2022, taking into account both drones and various types of missiles, Yuriy Ihnat, head of communications for Ukraine’s air force, told The Associated Press. The attack targeted several regions, including western Ukraine, far from the front line.

Poland and allied countries scrambled aircraft to ensure the safety of Polish airspace, the country’s air force said, according to Associated Press.