Eleven hostage-takers were killed as Algerian troops launched a final raid Saturday on a gas plant where foreign workers were being held captive, BBC reported Saturday.
Algerian state news agency APS said seven hostages were killed by their captors as the troops tried to free them.
The nationalities of the dead hostages were not known.
The militants had been involved in a stand-off since Thursday after trying to occupy the remote site.
Earlier, Xinhua said that as many as 31 workers, including 19 foreign nationals, have been killed since the beginning of the Algerian army's rescue operation.
A source told Xinhua that nine militants were also killed, while three were arrested alive, since the army's Special Forces launched the operation Thursday at the Tinguentourine gas field.
The source said there were still a few hostages in the gas field complex, specifying that the Special Forces were advancing compartment by compartment in the facility.
The Special Forces found bodies as well as workers hiding in the corners of the facility, the source told Xinhua.
Algeria's official APS news agency earlier said more than 670 hostages, including 573 Algerians and about 100 foreigners, were freed in the raid, which also left 12 hostages and 18 militants dead.