Residents in two northern Nigeria cities remained under curfews Wednesday, after three days of violence that killed dozens.

Nigerians in the cities of Kaduna and Damaturu were confined to their homes 24 hours-a-day, leaving the streets virtually deserted. Witnesses report a large number of soldiers patrolling the streets.

There were conflicting death toll estimates Wednesday, ranging from 80 to 95 killed since Sunday.

The wave of unrest began sweeping northern Nigeria on Sunday, when the Islamist militant group Boko Haram attacked three Christian churches in Kaduna state.

The suicide bomb attacks killed at least 21 people and sparked reprisal attacks by Christians.

The violence spread to Damaturu on Monday and Kaduna on Tuesday.

Authorities have blamed the unrest on both Christians and Muslims.

Nigeria has a history of sectarian violence, especially in the country's Middle Belt, where the mainly Muslim north meets the predominantly Christian south.

Boko Haram says it is fighting for an Islamic state and does not recognize the Nigerian government or the constitution.