Kidnap theory credible for French aid workers in Yemen

* Aid workers disappeared in southern province

* Yemen in throes of civil unrest

PARIS, May 30 (Reuters) - France said on Monday it was credible that three aid workers who disappeared in Yemen at the weekend had been kidnapped, although it had still not received any claim of responsibility.

The workers disappeared in Yemen's southern province of Hadramout on Saturday and a local security official said on Saturday they were believed to have been kidnapped. [ID:nLDE74R0CB}

"With each passing hour, the assumption it is a kidnapping gains credibility," Foreign Ministry spokesman Bernard Valero said. "But without a claim of responsibility, it is still to early to draw definitive conclusions."

The three work for Lyon-based Triangle Generation Humanitaire in the Arabian Peninsula country, which has been in the grip of civil unrest for months.

Kidnappings of Western tourists or workers by tribes seeking ransom or concessions from the government have been frequent in Yemen, one of the poorest Arab countries. Most of the hostages have been freed unharmed.

France has nine nationals already held overseas including four in the Sahel region, two in Afghanistan, two in Ivory Coast and one in Somalia.