The attack came on the third day of a planned prisoner swap between Russia and Ukraine, the only tangible outcome from peace talks in Istanbul earlier this month.

The massive attack across Ukraine followed another large strike the night before, and casts more doubt on the U.S.-brokered peace process.

Amid a historic prisoner exchange, Russia unleashed massive drone strikes over Kyiv and other Ukrainian territories. Meanwhile, drone strikes rattled Moscow, indicating the escalation of tensions