At least 20 foreign hostages, including some Americans, escaped Thursday from an Al Qaeda-linked group who had taken over an Algerian natural gas complex in the Sahara desert, a security official reported.

But the militant group said 35 hostages and 15 of their members have been killed after Algerian helicopters attacked the facility in a strafing run, the Associated Press reports. The claim could not be independently verified.

The group claiming responsibility -- called Katibat Moulathamine or the Masked Brigade -- told a Mauritanian news outlet that its leader was among the dead in the attack, which occurred when the kidnappers tried to leave the complex. They say seven hostages are still alive in Algeria, including Americans and citizens of the UK, Belgium and Japan.

A US military source tells Fox News that the attack did happen, but could not provide further details. Some of the Americans believed to have escaped have called home to their families, US official sources say...

The US State Department is working to account for all of the Americans reported missing.

At least 20 gunmen attacked the vast complex early Wednesday in retaliation for France's military intervention against Al Qaeda-linked rebels in neighboring Mali. Militants phoned Mauritanian media Wednesday to say one of its affiliates had carried out the operation and that France should end its intervention in Mali to ensure the safety of the hostages.

The militants, who initially claimed to have 41 hostages -- including seven Americans -- have been in a tense standoff since then, surrounded by the Algerian military, which has helicopters flying over the Ain Amenas gas plant, 800 miles south of the capital of Algiers. BP, which partly owns the plant, said in a statement on its website Thursday that the situation was still ongoing.

Some 30 Algerian workers fled the facility earlier Thursday, suggesting that the militants are having trouble managing the many hostages they have taken at the gas complex, the third largest in oil-rich Algeria.

The France-based head of a catering company at the plant told French media before the latest escape that some 40 foreigners appeared to be held hostage in a separate area from the Algerian workers.

Regis Arnoux of the Mareseille-based CIS Catering company said while electricity to the plant has been cut, it had at least three weeks of food supplies.

Algerian authorities, meanwhile, were talking with tribal Algerian Tuareg leaders in hopes of mediating the dispute.

Two people, one a Briton and the other Algerian, were killed in the militants' initial assault on the gas complex, which the US Defense Secretary Leon Panetta has called "a terrorist attack." The kidnapping is one of the largest ever attempted by a militant group in North Africa.

The hostage-takers are reportedly seeking a safe passage out of the isolated area, something Algerian authorities have already rejected.

READ FULL SOURCE ARTICLE: 01/17/2013