A large bomb explosion rocked an area near a church in the northern Nigerian city of Kaduna on Easter Sunday, residents and police said, though it was unclear if there were casualties.
"We have a bomb explosion. We are trying to sort things out," police spokesman Aminu Lawal told AFP, declining to comment further.
"I was in my house when I heard a loud explosion that shook my house, causing my ceiling to cave in," one local resident told AFP by phone.
He ran to the site, which had been cordoned off, but he said he could see damage to the Assemblies of God Church and cars.
The Nigerian Red Cross said six people had died. The emergency services had earlier put the number of dead at 18.
The blasts, which caused extensive damage, happened close to restaurants, a hotel and at least one church.
Residents speculated that the explosives were placed in a badly-mangled car, seen outside the church, as a service was taking place. A hotel is also located in the area.
Islamist group Boko Haram carried out a series of attacks on churches and other locations on Christmas Day. The worst of those attacks occurred at a church outside the capital Abuja, where 44 people died.
Authorities as well as foreign embassies had warned of the possibility of an attack on Easter Sunday.