Explosions heard in Kyiv after ballistic missile warning: AFP

An AFP reporter heard several explosions in Ukraine's capital early Sunday as Kyiv's authorities warned of incoming ballistic missiles.

Russia has increasingly been using long-range missiles in its grinding war against Ukraine, which has responded by carrying out drone strikes deep inside Russian territory in recent weeks.

"Air raid alert in Kyiv due to the ballistic missile threat," the capital's military administration said on Telegram, urging people to head to shelters at around 2:00 am (2300 GMT).

Kyiv Mayor Vitali Klitschko reported "explosions in the capital", which he said was "under ballistic missile attack".

Soon after, a fire broke out in a non-residential building in the capital's Obolonsky district, Klitschko and authorities said, without specifying any casualties.

Meanwhile, Russia fended off another drone swarm approaching its capital.

Moscow Mayor Sergei Sobyanin said in a series of posts on the state-backed MAX platform that Russian forces downed around 28 drones "flying towards Moscow".

Ukrainian forces have repeatedly struck Russian oil refineries and military infrastructure, while Moscow has pressed its offensive in the east and launched deadly barrages on cities including Kyiv, at times using North Korean ballistic missiles according to Ukrainian officials.