At least 34 hostages and 15 Islamist militant captors have been killed in Algerian army air strikes on a remote gas treatment plant where a mass abduction took place, a Mauritanian news agency reported Thursday, citing one of the kidnappers.

"We're going to hold the rest of the hostages and we'll kill them if the Algerian army approaches," the spokesman for the kidnappers told the private ANI news agency, adding that the group's chief of command, identified as Abu al-Baraa, was among the dead.

Abu al-Baraa had earlier been the militant group's spokesman.

The new spokesman, who was not identified, said the kidnappers had been trying to transport some of the hostages to a safer place when Algerian military planes bombarded the convoy.

The nationality of the hostages allegedly killed remains unclear.

The spokesman made no mention of reports by Algerian officials that 30 Algerian captives had escaped.

The group of militants calling itself the "Signers in Blood" cell, part of the "Masked Brigade," said it carried out the mass abduction Wednesday in retaliation for a French military assault on Islamist militants in northern Mali, which borders Algeria to the south.

They said they were holding 41 foreign hostages, along with a unspecified number of Algerians, and would guarantee their well-being in exchange for an end to the French military offensive in the neighboring country.

In a communique sent Wednesday to ANI, the group, which is reportedly led by Mokhtar Belmokhtar, said seven Americans and a number of French and Britons, as well as other Europeans, were among the hostages.

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 state-owned Algerian oil company Sonatrach, Britain's BP 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 Dahou Ould Kablia, who said that Algiers would not negotiate with terrorists. EFE