A Ukrainian drone attack has hit a building in Moscow, causing an explosion that was heard across the city's business district, Russian officials have said.

Mayor Sergei Sobyanin said air defences had shot down the drone with its debris falling on the city's Expo Center.

It marks the latest in a series of such attacks on the Russian capital.

Unverified footage on social media appeared to show thick grey smoke rising into the night sky over Moscow.

There was no immediate comment from Ukraine.

The attack occurred at around 04:00 local time (01:00 GMT), Russia's defence ministry said on Telegram.

It said that, after activating the city's air defence systems, the drone had "changed its flight path", falling on a non-residential building on the Krasnopresnenskaya Embankment, an area of Moscow which hosts a number of government buildings.

It added that the debris had not causes a fire and that no-one was injured, while Mr Sobyanin said the drone had caused "no significant damage" to the Expo Center.