Nigerian police probe clashes that killed 700

Maiduguri, Nigeria - Police in northern Nigeria say they're investigating how a homegrown Islamist sect unleashed a wave of violence that left more than 700 people dead in clashes last week.

Borno state police spokesman Isa Azaza says police are holding 20 men suspected to be members of the Boko Haram sect. He says some of the men were seized with gunpowder, vats of acid, aluminum containers for bomb-making, assault rifles and black-and-white flags with Arabic inscriptions.

Azaza said the group was well organized in its attacks on police stations and government installations.

The city of Maiduguri was calm Monday morning, with police conducting street patrols.

The radical group sparked the violence with a July 26 attack on a police station in Bauchi. Violence quickly spread to three other northern states.