Nigerian police have detained hundreds of people belonging to an Islamic community in the state of Niger.
The arrests on Saturday came weeks after a radical sect killed almost 800 people in the north of the country.
About 1,500 police officers backed by reinforcements from the capital, Abuja, had surrounded the compound of the Darul Islam community on the edge of the town of Mokwa early on Saturday, said Mike Zuokumor, Niger state police chief.
"We received a series of reports about the activities of the sect from neighbouring communities, the local government and the emirate [traditional leader]," Zuokumor said.
"Some of them were expressing apprehension concerning the activities of the group and it is our duty to ensure law and order among the citizens of the state."
Clashes three weeks ago between security forces and members of an Islamist sect called Boko Haram killed close to 800 people in the northeastern city of Maiduguri, more than 800km away from Niger state.
The government ordered an investigation into the violence after Mohammed Yusuf, Boko Haram's leader, was captured by security forces and died in custody.
Saturday's arrests were peaceful and no shots were fired.
Amrul Bashir Abdullahi, the leader of Darul Islam originally from the northern state of Kano, said after being detained that he had lived in Mokwa for 17 years.
"We are not against Western education as we are being accused, but we have our own belief which is not in any way an infringement of the state authorities," Abdullahi said.
"We decided to create a camp for ourselves outside the community because of the problems in the larger society. These are problems of corruption, drunkenness, prostitution and so on which Allah forbids."
Zuokumor said police wanted to find out more about the beliefs of Darul Islam and that any members found to be from neighbouring countries would be deported.
He said police had received reports that Darul Islam was forcibly holding women to be the wives of sect members.
Local media said as many as 3,000 people were believed to live in Darul Islam community.
Male members dress in white robes while its women are fully covered in black.
Nigeria's 140 million population is divided between Christians in the south, and Muslims mainly in the north, where 12 of the 36 states adopted sharia (Islamic law) in 2000.