20120110
AP
MAIDUGURI, Nigeria (AP) — Authorities say a radical Muslim sect has killed a secret police officer in northeast Nigeria as part of its widening sectarian battle against the oil-rich nation's weak central government.

Borno state police commissioner Simeon Midenda said the attack happened Monday in the town of Biu. Midenda said the gunmen from the sect known locally as Boko Haram attacked after the officer of the State Security Service left a mosque.

At least 53 people have been killed in recent days by Boko Haram, according to an Associated Press count. Boko Haram says it has started specifically targeting Christians, exploiting religious tension in the nation.

In Washington, U.S. State Department spokeswoman Victoria Nuland condemned the violence in Nigeria and expressed condolences to the victims. She said Boko Haram was "trying to rip the country apart."