Bomb blasts damaged five churches in four cities in Nigeria's northern Kaduna state on Sunday, injuring dozens of worshippers and leading to an immediate curfew, officials said.

The number of casualties in the blasts in the neighboring cities of Zaria and Kaduna and in the southern Christian-dominated Nassarawa and Barnawa was not immediately clear. Police and the military cordoned off the areas.

A car bombing near a church in northern Nigeria as services were being held on Easter Sunday killed at least 20 people, wounded 30 others and put the country on alert over fears of further attacks.

The explosion, a stark reminder of Christmas Day attacks that left dozens of people dead in Africa's most populous nation and largest oil producer, hit the city of Kaduna, a major cultural and economic center in the north.