ALGIERS, Algeria - As Algerian army helicopters clattered overhead deep in the Sahara desert, Islamist militants hunkered down for the night in a natural gas complex they had assaulted Wednesday morning, killing two people and taking dozens of foreigners hostage in what could be the first spillover from France's intervention in Mali.
The Algerian army has surrounded the complex and about 1,000 miles from the coast, there is no obvious way for the kidnappers to escape in their four-wheel-drive vehicles with their hostages.
A militant group claimed responsibility for the rare attack, saying it came in revenge for Algeria's support for France's military operation against al-Qaida-linked rebels in neighboring Mali. The militants said they were holding 41 foreigners from the energy complex, including seven Americans.
It was not immediately possible to rectify the discrepancies in the number of reported hostages. Their identities were also unclear, but Ireland announced that they included a 36-year-old married Irish man and Japan, Britain and the U.S. said their citizens were involved as well.
The group - called Katibat Moulathamine - phoned a Mauritanian news outlet to say one of its affiliates had carried out the operation at the Ain Amenas gas field, located 800 miles south of Algiers, the Algerian capital, and that France must cease its intervention in Mali to ensure the safety of the hostages.
BP, together with the Norwegian company Statoil and the Algerian state oil company Sonatrach, operates the gas field.
In Rome, 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-Qaida activities in Pakistan, Afghanistan and in the United States on Sept. 11, 2001.
Algeria's top security official, Interior Minister Daho Ould Kabila, said that "security forces have surrounded the area and cornered the terrorists, who are in one wing of the complex's living quarters."
He said one Briton and one Algerian were killed in the attack while a Norwegian and two other Britons were among the six wounded.
"We reject all negotiations with the group, which is holding some 20 hostages from several nationalities," Kabila said on national television, raising the specter of a possible armed assault to try to free the hostages.
The head of a catering company working on the base told the French Journal de Dimanche that helicopters were flying over the complex and the army waited outside. There were even reports of clashes between the two sides and a member of the militant group told the Mauritanian news outlet they had already repelled one assault by Algerian soldiers late Wednesday night.
Hundreds of Algerians work at the plant and were also taken hostage in the Islamist attack, but the Algerian state news agency reported they were gradually released unharmed Wednesday in small groups.
The Algerian minister said the militants appeared to be hoping to negotiate their departure from the area, something he rejected.
In Washington, U.S. State Department spokeswoman Victoria Nuland confirmed that "U.S. citizens were among the hostages."
The caller to the Nouakchott Information Agency, which often carries announcements from extremist groups, said the kidnapping was carried out by "Those Who Signed in Blood," a group created to attack the countries participating in the offensive against Islamist groups in Mali.
The Masked Brigade was formed by Belmoktar, a one-eyed Algerian who recently declared he was leaving the terror network's Algerian branch, Al-Qaida 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.
The name of his group could be a reference to the nomadic Tuareg inhabitants of the Sahara, known for masking their faces with blue veils.