At least three people have been killed in a terror attack at a mosque in Tanzania, officials have said. The attack was carried out at the Masjid Rahmani mosque in Mwanza, in the north-west of the country, on the evening of 19 May.

Around 15 masked assailants stormed the mosque and used improvised explosives, machetes and axes against the worshippers.

The victims include the the imam of the mosque, Ferouz Ismail Elias, Mwanza Police explained and added that several other worshippers sustained injuries.

Witnesses said the attackers asked worshippers why they were praying while "our comrades are in prison" before attacking them.

No group has claimed responsibility for the attack, which occurred days after a video emerged of masked people alleging they were the East African branch of the Islamic State (Isis/Daesh) group. The people claimed they were in Tanzania's coastal region of Tanga.

Tanzania's Home Affairs minister Charles Kitwanga told the BBC security forces were investigating the possible presence of jihadists in the country.

UPDATE 12:40 pm

Three people have been arrested in connection with the attack, the police said.