NIAMEY (Reuters) - At least 18 soldiers and four suspected Islamists were killed in a fierce gunbattle following a dawn car bomb attack at a barracks in the northern Niger town of Agadez, military sources and a local official said.

"There are 18 soldiers and four attackers dead in Agadez," said one source.

"One of the attackers has taken two or three soldiers hostage and is holed up in a house. We have him surrounded."