KYIV, Ukraine (AP) — Ukraine’s capital came under a large-scale Russian drone and missile attack early Saturday with explosions and machine gun fire heard throughout the city, forcing many Kyiv residents to take shelter in underground subway stations. The nighttime Russian attack came hours after Russia and Ukraine began a major prisoner exchange, swapping hundreds of soldiers and civilians in the first phase of an exchange that was agreed on by the two sides at a meeting in Istanbul last week. The agreement was a moment of cooperation in otherwise failed efforts to reach a ceasefire in the 3-year-old war.