Algerian special forces are still hunting Islamist militants who overran a BP gas plant as freed British hostages spoke of their fears for their colleagues still trapped on the site.
The Algerian state news agency, APS, reported that about 100 foreign workers had been released from a total of 132 seized by the militants when they stormed the remote desert facility on Wednesday.
At least 10 UK nationals were understood to still be "at risk" at the plant at In Amenas, close to the Libyan border, as the hostage crisis headed towards a fourth day.
Footage of several British workers said to have escaped the siege has been shown on Algerian state television. One man said: "The gendarmes did a fantastic job. They kept us all nice and safe and fought off the bad guys. I never really felt in any danger, to be honest."
Another said: "I feel safe at the moment but I won't feel 100% happy until I'm back in the UK. My heart goes out to the guys that are still there and hopefully everyone comes home safe because, at the end of the day, it's only work."
The Algerian government said that an unspecified number of foreigners had died during the military rescue operation, which began on Wednesday morning. Eighteen of the militants were also reported to have been killed - suggesting that around a dozen of the original group of about 30 could still be at large.
A Mauritanian news site reported that the remaining militants were demanding the release of two terrorists held in the United States, including 1993 World Trade Centre bombing mastermind Omar Abdel Rahman, in return for the release of two US captives.
Despite the casualties among the hostages, an Algerian government source quoted by APS strongly defended the military operation, saying it had prevented a "true disaster" which would have caused "immeasurable" human and material damage.
Prime Minister David Cameron said Britain would do "everything we can to hunt down" those behind the "brutal and savage" attack.
It was reported that two UK workers were among the casualties, which would bring the British death toll to three after one was killed in Wednesday's initial raid by the militants.