Russia and Ukraine have swapped hundreds more prisoners of war, the third and last part of a major swap, hours after a massive attack by Moscow, killing at least 12.

The Ukrainian and Russian militaries exchanged massive air strikes overnight Saturday, even amid a planned swap of some 303 prisoners of war from each side.

Russia and Ukraine have completed the first phase of what is expected to be the biggest prisoner exchange since the start of the war, with almost 800 people released on Friday.

NATO scrambled fighter jets after Russia launched a massive air attack on Ukraine for a second consecutive night – killing at least seven people. Dozens of people were injured, including

Ukraine's capital Kyiv was coming under a combined drone and missile attack early on Saturday, Mayor Vitaly Klitschko said. Timur Tkachenko, head of the capital's military administration, said two fires had broken out in the city's Sviatoshinskyi district.