U.S. embassy officials say they have requested assistance from Chad's government in gaining to the release of an American humanitarian worker being held by rebels in the north. The rebels accuse him of spying for Chad's government.  Naomi Schwarz has more from Dakar.

American Embassy Public Affairs Officer Solomon Atayi says the embassy is awaiting a response from Chad's government.

"The American embassy has contacted the Chadian government and we are in touch with the government right now and have requested their assistance in resolving the situation," he said.

A government official said negotiations with the rebel group are already under way.

Steve Goldbold, an American evangelical missionary, was seized by rebels from the Movement for Democracy and Justice in Chad earlier this month. He was in the region working on a well-digging development project funded by the American embassy.

He is being held in Zoumri, in the mountainous Tibesti region in Chad's far north.

Chad's eastern and northern regions have been embroiled in conflict.  Ethnic conflicts, multiple rebel groups, and spillover from Sudan's Darfur conflict, have left the region in turmoil.

The Movement for Democracy and Justice launched an armed insurgency in 1998 led by President Idriss Deby's former defense chief, Youssouf Togoimi. Togoimi was killed by a landmine in 2002. The rebel group signed a peace deal with the government in 2005, but splinter groups have refused to sign it.

They have accused Goldbold of being a spy for Chad's government. Atayi says this is untrue.

"All we know is that he is a humanitarian," he added.  "He worked for a humanitarian organization."

Annette Rehrl, a humanitarian worker in eastern Chad, says aid workers need to be especially careful in conflict zones.

"If you are working in a conflict environment then you always need to be extremely careful not to caught in between lines because it is enough to be at the wrong place at the wrong momentm," she noted.

She says Chad's government has expressed support for humanitarian workers there, and she has not experienced problems with the local community.

The past week has seen an upsurge in violence in Chad, particularly in the eastern border region near Sudan. The situation had been relatively calm during the month-long Islamic holiday of Ramadan.

On Tuesday, the government declared state of emergency in three regions in the east and north. A total of 3,000 European Union peacekeepers are set to arrive next month.