Explosion heard at Nigeria Agip oil facility-sources

YENAGOA, Nigeria, March 16 (Reuters) - An explosion was heard at a Nigerian onshore oil flowstation operated by Agip (ENI.MI) in the Niger Delta on Wednesday, security sources said, but the cause was not immediately clear.

A joint military task force confirmed there had been an explosion in Bayelsa state in the Niger Delta but did not specify the exact location. Italian oil firm Agip was not immediately available for comment.

The explosion was heard in the early hours at Agip's Clough Creek oil flowstation in Bayelsa, one security source said.

An email, saying it was sent by Nigeria's main militant group, warned on Monday of renewed attacks on Africa's biggest oil and gas industry but most of the recent damage caused to Nigeria's oil infrastructure has been from gangs stealing oil, rather than militant strikes. (Reporting by Samuel Tife; writing by Joe Brock)