Algeria siege: 'Around 30' hostages unaccounted for Published duration 19 January 2013

media caption Some freed British hostages told Algerian TV they were "relieved to be out"

Hundreds of hostages have been freed from militants at an Algerian gas facility, state media say, but about 30 foreigners are still unaccounted for.

State-run APS news agency said 573 Algerians and 'around 100' of 132 foreign workers were freed at the In Amenas facility.

The militants remained holed up at the site, APS said. About 10 Britons are thought to be still held.

The agency says 12 workers died since a rescue operation began on Thursday.

The 12 included Algerians and foreigners. Eighteen of the hostage takers were also "put out of action", APS said, citing a "provisional" total.

The US state department has confirmed that one US hostage, Frederick Buttaccio, died in the operation, but gave no details of the circumstances.

"Out of respect for the family's privacy, we have no further comment," said state department spokesperson Victoria Nuland.

The Algieran news agency had previously issued a less precise total of freed foreign hostages, saying "more than half" of the 132 had been liberated.

Two workers, a Briton and an Algerian, reportedly died on Wednesday when the militants ambushed two buses that were taking foreign workers at the facility to the local airport.

After the attack on the buses, at 0500 local time on Wednesday, the militants drove to the installation and took Algerian and foreign workers hostage in the living area and the main gas facility at the complex.

At noon local time on Thursday, Algerian forces attacked as the militants tried to move some of their captives from the facility. The current situation is unclear, but reports on Friday morning said security forces were still searching for the hostage takers at the complex.

A security source told APS that Algerian special forces were seeking a "peaceful end" to the crisis.

The installation had been put out of action to avoid the risk of an explosion, the state news agency reported.

'No hiding place'

The UK Foreign Office has refused to confirm the latest figures from Algeria indicating that around 100 out of a total of 132 hostages have been freed.

Japan and Norway have both said they have nationals missing in the crisis. Officials from several countries, including Japan, Norway, Ireland, the US and Austria have also confirmed some of their nationals managed to escape.

French Foreign Laurent Fabius said the Algerian authorities had informed him that one French citizen, Yann Desjeux, was killed in the military operation, and that three others were rescued.

UK Prime Minister David Cameron told Parliament that he had been told by his Algerian counterpart, Abdelmalek Sellal, that it was a large site and troops were "still pursuing terrorists and possibly some of the hostages".

US Secretary of State Hilary Clinton told reporters that the "utmost care must be taken to preserve innocent life" in the handling of the crisis.

US officials earlier confirmed that there were still Americans being held at the site and re-iterated that the "United States does not negotiate with terrorists."

US Defence Secretary Leon Panetta told BBC Radio 4's Today programme that "we are not going to allow them to have a hiding place from which to conduct these terrorist acts".

'Prisoner exchange'

On Friday morning, a spokesman for the group thought to be behind the attack told the Mauritanian ANI agency - which has received several messages from the militants - that it would carry out further operations.

Algerian officials said the militants were operating under orders from Mokhtar Belmokhtar, who was a senior AQIM commander until late last year.

ANI quoted sources from Belmokhtar's group as saying that they wanted to exchange their American captives for two high-profile detainees in American jails.

They are the Egyptian Sheikh Omar Abdel-Rahman, convicted over the 1993 World Trade Center bombing in New York, and Pakistani scientist Aafia Siddiqui, who was convicted in 2010 of attempting to kill US military personnel.

An earlier statement purporting to come from the kidnappers says the raid was carried out in retaliation for the French intervention against Islamist groups, including al-Qaeda in the Islamic Maghreb (AQIM), in neighbouring Mali.

media caption David Cameron tells MPs that British citizens remain at risk, but that the number has been “significantly reduced”

But BBC security correspondent Gordon Corera says the kidnapping was a complex operation which is unlikely to have been planned and carried out since the surprising French intervention in Mali last Friday.

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.

BP said that hundreds of workers from international oil companies had been evacuated from Algeria on Thursday and that many more would follow.