The group of armed Islamic militants that on Wednesday kidnapped several dozen foreigners at a gas field in southern Algeria is demanding the end of the military offensive in Mali in exchange for guaranteeing the well-being of the hostages, which they say number 41.

In a second communique sent to the private Mauritanian news agency ANI, the group, which is led by Mokhtar Belmokhtar, said that it is holding seven Americans and a number of French and Britons, as well as other Europeans.

Algerian authorities acknowledged that "more than 20" hostages were taken by gunmen in the attack on a gas processing plant in the southeastern province of Ilizi, and they added that they had information that there were also Norwegians and Japanese in the group of hostages.

The attack, in which two people were killed and six were wounded, was staged by the "Signers with Blood" cell belonging to the "Masked Brigade," the group Belmokhtar heads.

It is not clear whether the group is affiliated with Al Qaeda in the Islamic Maghreb, given that Belmokhtar has had disagreements with AQIM.

In the second communique, the "Signers with Blood" say that the recently-launched French offensive against the Islamists who occupy northern Mali is "a world campaign of combat by the Jews and the crusaders."

Details are sketchy, but the attack apparently was staged on Wednesday morning first against a bus carrying workers at the natural gas installations operated by Algeria's Sonatrach, British Petroleum and Norway's Statoil near Algeria's border with Libya.

The two people killed in the attack were an Algerian and a Briton, and of the six wounded two were foreigners, according to Algerian Interior Minister Daho Uld Kablia, who said that Algiers would not negotiate with terrorists.

U.S. State Department spokesperson Victoria Nuland confirmed that several U.S. citizens are among the hostages but she refused to discuss other details of the situation.

Meanwhile, Norway said that 13 of its citizens had been taken hostage and Ireland confirmed that one of its citizens had been kidnapped.

From France, the CIS Catering company informed the Journal du Dimanche that 150 "Algerian employees" of its affiliate Cieptal had been "taken hostage" and "cannot leave. EFE