MAIDUGURI, Nigeria - Authorities say at least 61 people have died in northeast Nigeria over several days of fighting between security forces and members of a radical Muslim sect.

Police, military and mortuary officials in Borno and Yobe states said Saturday that the deaths come amid a series of attacks suspected to be carried out by the sect known as Boko Haram.

The fighting began Thursday, with gunshots and explosions echoing through the cities of Damaturu and Maiduguri.

Boko Haram has carried out an increasingly bloody sectarian fight against Nigeria's weak central government in its effort to implement strict Shariah law in Africa's most populous nation.