An undated image released by BP petroleum company shows the Amenas natural gas field in the eastern central region of Algeria, where militants raided and took hostages on Jan. 16, 2013. / AP/BP
ALGIERS, ALGERIA (CBSNews.com) - The hostage situation in an Algerian natural gas field escalated Thursday, with Islamic militants claiming that Algerian helicopter attacks have left 35 hostages and 15 captors dead.
Details were still emerging Thursday morning and there was no confirmation from the U.S. or other governments involved.
Meanwhile, multiple sources reported the earlier escape of some hostages, but details differed. An employee at the facility, partly operated by BP, told CBS News that 26 Algerians and four foreigners, including one American, had escaped, citing a briefing from BP officials. Two British and one French hostage accounted for the other foreigners.
One Algerian security official told the Associated Press on Thursday that 20 foreigners had managed to escape, including some Americans and Europeans.
Those reports were also unconfirmed by government officials.
Al-Qaeda-linked militants stormed the natural gas complex in the Sahara Desert on Wednesday, seizing up to 41 foreign hostages. Algerian forces have surrounded the militants at the plant since then, and have rejected demands for safe passage.
The group claiming responsibility -- called Katibat Moulathamine or the Masked Brigade -- said the attack was in revenge for Algeria's support of France's military operation against al Qaeda-linked rebels in neighboring Mali. Militants phoned a Mauritanian news outlet to say one of its affiliates had carried out the operation at the Ain Amenas gas field, and that France should end its intervention in Mali to ensure the safety of the hostages.
The Masked Brigade was formed by Belmoktar, a one-eyed Algerian who recently declared he was leaving the terror network's Algerian branch, al Qaeda in the Islamic Maghreb, to create his own group. He said at the time he would still maintain ties with the central organization based in Afghanistan and Pakistan.
On Thursday, the Al Jazeera television network spoke via telephone to three purported hostages, and to a man identifying himself as Aboul Baraa, who said he was the Katibat Moulathamine commander leading the operation at the Amenas gas field.
"Yesterday, the Algerian army deliberately opened fire and they injured some of the hostages from Japan and South Korea," Baraa told Al Jazeera. "If the army withdrew from the area, lifted this siege, and abandoned their obstinate approach, this can open the door for negotiations with governments of the hostages' countries."
A man identifying himself as a Japanese hostage told the network that he and a Norwegian hostage had been wounded by sniper fire. Two others, who identified themselves as a Briton and an Irish national, said they had communicated to their respective embassies that the situation was "deteriorating," and urged the Algerian military to pull back from the confrontation and stop engaging the kidnappers.
The Irishman said the "message does not seem to be getting through," warning that the incoming fire from Algerian troops was continuing, "up until recently, about 10 minutes ago, they were still firing into the camp."
It was impossible to confirm the identities of the hostages, or whether they were being forced to make their statements under duress. The men said their captors were treating them well.
CBS News correspondent Margaret Brennan reports the State Department has only confirmed that three Americans are among those taken hostage, and that 10 in total worked at the facility.
The government was in talks throughout the night with the U.S. and France over whether international forces could help against the militants, who have said 41 foreigners, including seven Americans, were being held after the assault on one of oil-rich Algeria's energy facilities, 800 miles from the capital of Algiers. Two foreigners, one of them a Briton, were killed.
An official told the AP that Algerian officials also contacted tribal elders among Algerian Tuaregs, who are believed to have close ties with Islamic militants linked to al Qaeda. The official said the government hoped the Tuaregs might help negotiate an end to the standoff.
BP, the Norwegian company Statoil and the Algerian state oil company Sonatrach, operate the gas field. A Japanese company, JGC Corp, provides services for the facility as well.
It was not immediately possible to account for the discrepancies in the number of reported hostages. Their identities also were not clear, but Ireland announced that they included a 36-year-old married Irish man. Japan, Britain and the U.S. said their citizens were taken. A Norwegian woman said her husband called her saying that he had been taken hostage.
British Foreign Secretary William Hague told BBC radio on Thursday that he has dispatched a team to Algeria to help at the British embassy there.
"Excuses being used by terrorists and murderers who are involved - there is no excuse for such behaviour, whatever excuse they may claim," he said.
"It is absolutely unacceptable, of course. It is, in this case, the cold-blooded murder of people going about their business. So there is no excuse, whether it be connected to Libya, Mali or anywhere else."
In Rome on Wednesday, U.S. Defense Secretary Leon Panetta declared that the U.S. "will take all necessary and proper steps" to deal with the attack in Algeria. He would not detail what such steps might be but condemned the action as "terrorist attack" and likened it to al Qaeda activities in Pakistan, Afghanistan and in the United States on Sept. 11, 2001.
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