Ukrainian security forces have killed around 20 pro-Russian fighters during clashes in the south-eastern city of Mariupol, according to Ukrainian Interior Minister Arsen Avakov.

One soldier has been killed, and five injured, Avakov wrote on Facebook, adding that four pro-Russian fighters were arrested.

According to the minister, the clashes occured when a group of 60 “terrorists” attacked a police station in the centre of the city.

Authorities in the Donetsk region, meanwhile, said three people had died and 25 were injured in the clashes.