CNN producers in the Ukrainian capital heard several explosions and saw smoke over the city, as an air raid alert stretched on for hours. Massive fires lit up the night sky over the capital, video by Reuters news agency showed.

Ukraine has been relatively successful at intercepting the massive numbers of drones that Russia uses in its large-scale attacks. But in recent weeks, Moscow has repeatedly exploited Kyiv’s near-zero stocks of Patriot interceptor missiles, which are needed to defend against faster-moving ballistic missiles.