About 650 hostages have been freed from militants at a gas facility in Algeria, state media report, but about 60 foreigners are still being held.
State-run APS news agency said those freed at the In Amenas installation included 573 Algerians and more than half of 132 foreign workers.
The militants remained holed up at the site and the Algerian army wanted a "peaceful end" to the crisis, APS said.
At least four foreign workers died when troops moved in on Thursday.
A "comprehensive total" of the hostages still held was not available and some of them had taken refuge at various points around the site, a security source told APS.
The installation had been put out of action to avoid the risk of an explosion, the agency reported.
Meanwhile, BP said on Friday that hundreds of workers from international oil companies had been evacuated from Algeria on Thursday and that many more would follow.
On Friday morning, a spokesman for the group thought to be behind the attack told the Mauritanian ANI agency that it would carry out further operations.
He warned Algerians to "stay away from the installations of foreign companies as we will strike where it is least expected".
Algeria has yet to give precise casualty figures from Thursday's rescue attempt.
The state-run APS news agency cited local officials as saying two Britons and two Filipinos were killed. Two others, a Briton and an Algerian, died on Wednesday when the militants ambushed a bus that was taking foreign workers at the facility to the local airport.
A spokesman for the militants told the ANI agency that 35 hostages and 15 militants had been killed in Thursday's operation. One Algerian official said the figures were "exaggerated".
The In Amenas gas field is operated by the Algerian state oil company, Sonatrach, along with the British oil company BP and Norway's Statoil.
It is situated at Tigantourine, about 40km (25 miles) south-west of the town of In Amenas and 1,300km (800 miles) south-east of Algiers.
APS cited local officials as saying the military operation at the gas facility's living quarters, where most of the hostages were held, had ended on Thursday night.
"Hostages are still being held at the Tigantourine gas treatment plant, which is surrounded by special forces," APS added.