DOZENS of worshippers were killed today in a co-ordinated terrorist assault, believed to be led by extremist group Boko Haram, on the central mosque in the city of Kano.

Three large explosions hit the mosque before a number of gunmen began an indiscriminate shooting spree.

Emir of Kano Muhammad Sanusi usually leads prayers in the mosque, although he is believed to be in Saudi Arabia at the moment.

The emir, who was governor of Nigeria's central bank until earlier this year, recently urged people to arm themselves against Boko Haram, which has killed more than 2,000 people this year.

He is reported to have told a prayer meeting earlier this month that people should "acquire what they need" to protect themselves.

A police spokesman called the emir's comments a "call for anarchy," demanding that they should not be acted on.

Boko Haram has targeted the city, the largest in northern Nigeria, several times during its five-year insurgency.