ABUJA, May 30 (Xinhua) -- At least 25 people were killed when a deadly suicide bomb attack hit a mosque in northeast Nigeria's Maiduguri city on Saturday, witnesses told Xinhua.

A suicide bomber blew himself up inside a mosque near the Monday Market and corpses were seen lying on the floor, Yusuf Ali, a witness said. The attack came one day after President Muhammadu Buhari was sworn in and vowed to combat militant group Boko Haram.

At least 28 others were injured as the male suicide bomber detonated his explosive device during afternoon prayers by Muslim faithful in the large mosque, Ali said.

A rescue worker said more than 25 bodies were evacuated at the scene of the blast.

Most officials, including security chiefs in the state, declined to comment on the casualties figure.

One support staff at a state-run hospital located a few kilometers away from the scene said nearly 20 bodies were received, while others were taken to other facilities within the metropolis.

"Most of the corpses parked from the scene of the blast could not be identified," added the medical support staff who preferred to be anonymous.

A Muslim cleric, Yushau Danjuma, said the bomber strolled into the mosque, pretending to be part of the congregation. "I noticed when he came, thinking he entered the mosque to join others to pray but soon as the prayers started, he detonated the explosive devices wired round his body," he said.

Kashim Shettima, governor of the northern Borno State, said security operatives had commenced investigation on the incident which he described as "an act of cowardice". Enditem