ALGIERS — Sixteen foreign hostages being held by Islamist fighters who attacked a gas plant in the Algerian desert were freed on Saturday, a source close to the crisis said.

Those freed included two Americans, two Germans and one Portuguese, the source told Reuters. The nationalities of the others were not immediately clear.

A number of foreigners were being held hostage at the gas plant nearly 48 hours after a failed rescue attempt killed at least 12 of them, a security source said.

Al-Qaeda-linked gunmen said after Thursday's rescue raid they still held seven foreigners — three Belgians, two Americans, one Japanese and a Briton — inside the sprawling Sahara complex in northeast Algeria near the border with Libya.

An Algerian security official put the number of foreign hostages at 10, but more workers also remain unaccounted for, including at least 10 Japanese and eight Norwegians.

Algerian media slammed the authorities' silence on the incident, saying that most of the information about the attack had come from international news outlets via the Mauritanian news agency ANI, which had received messages from the group.

A spokesman for the "Signatories in Blood," headed by jihadist commander Mokhtar Belmokhtar, said 34 hostages were killed when Algerian special forces raided the plant on Thursday a day after they seized it.

The veteran Algerian Islamist has claimed responsibility for Wednesday's militant assault on the gas plant. According to Algeria's national news agency APS, the military operation on Thursday killed 12 hostages and 18 of their captors, but also freed 100 of the 132 foreigners held.

The group is demanding an end to French intervention in neighboring Mali, ANI quoted sources close to Belmokhtar as saying.

France now has 2,000 troops on the ground in Mali as part of a drive against Islamist militants holding the north of the country, Defence Minister Jean-Yves Le Drian said Saturday.

That was 200 more than a day earlier, said the minister during a visit to the western port of Lorient, adding that a further 900 French soldiers were supporting the operation from bases outside Mali.

French defense officials on Saturday said they had never stated that France was aiming to have a total of 2,500 soldiers on the ground in its former colony in West Africa. That figure was widely used in the media.

Le Drian said Saturday that "perhaps we will go beyond that," and added that "in any case, around 4,000 troops will be mobilised for this operation" in Mali itself and elsewhere. — Agencies