UPDATE: Cameroon Mosque Bomber Was 'Worshipper'

The suicide bomber who struck at a mosque in northern Cameroon was praying alongside worshippers when he blew himself up, a security source said, AFP news agency reports.

"Eleven worshippers were killed at the scene. A twelfth died of his wounds in hospital," the source added.

The bombing came after two people were killed overnight in the same area in another attack blamed on Boko Haram, the security source is quoted by AFP as saying. 

Another source close to the security services confirmed the blast killed 12 people and the bomber, it adds.

Fighters from Nigeria's militant group Boko Haram has been carrying out attacks across the border in northern Cameroon.

The group's six-year campaign to establish an Islamic state in north-east Nigeria has killed at least 17,000 people and made about three million others homeless.

'Deadly blast' at Cameroon mosque

A suicide bomber has killed at least 10 people and wounded one other at a mosque in northern Cameroon, officials in the Far North region have said, Reuters news agency reports. 

No group has said it carried out the attack.

However, Nigeria's Islamist militant group Boko Haram has stepped up attacks in neighbouring Cameroon, Chad and Niger since last year.