Mobile phone service has been cut in areas of northeast Nigeria as the military sends more soldiers to the region to fight Islamic extremists.

An Associated Press journalist in Maiduguri, the capital of Borno state, found services unavailable since early Thursday morning. Mobile phone numbers belonging to government officials and military officials there and in neighboring Yobe state could not be reached.

A military spokesman in Nigeria's capital, Abuja, did not respond to requests for comment. A spokeswoman for MTN, the country's dominant carrier, would only say "no comment" when asked if the government told them to turn off service in the region.

President Goodluck Jonathan placed Adamawa, Borno and Yobe states under emergency rule on Tuesday night. Authorities announced a curfew Thursday for Adamawa state.