Another 16 hostages freed and seven more killed, reports say, and 11 more members of jihadist group killed in battle
Algerian security forces launched their "final assault" on jihadists at the In Amenas gas facility as reports said another 16 hostages had been freed and seven more killed.
Eleven fighters from the al-Qaida-linked Signers in Blood faction died in the battle at the desert plant in the east of the country, Algerian state news agency APS reported.
The hostages freed on Saturday included two Americans, two Germans and one Portuguese, a source close to the crisis told the Reuters news agency. The nationalities of the others were not immediately clear. Those who died were killed by their captors.
The source said Algerian special forces earlier found 15 burned bodies, although it was unclear whether these were hostages or militants. Efforts were under way to identify them.
The assault by the Algerian military came as the British foreign secretary, William Hague, said fewer than 10 Britons remained "at risk or unaccounted for" in the hostage crisis.
Hague earlier said on Twitter that the crisis would remain the government's "top priority until every British national is accounted for".
His comment on Twitter came before he chaired another meeting of the Cobra emergency committee. Hague added: "My thoughts are also with the families of everyone affected, particularly those still waiting for news of their loved ones."
Algerian authorities gave permission to the British ambassador to go to the gas plant with a small consular team, Sky News reported, which suggested that the armed standoff was coming to an end.
A plane carrying a 15-strong rapid deployment team of British consular staff, foreign officials, police and Red Cross counsellors landed in the desert outpost of Hassi Messaoud on Friday afternoon.
One Briton was among the 12 Algerian and foreign workers reported killed when militants attacked the site on Wednesday.
Details emerged on Saturday about the leader of the jihadist attack on the BP plant in Algeria. Abdul Rahman al Nigeri, an Arab from Niger also known as Abu Dujana, is a close associate of Mokhtar Belmokhtar, a former leader of al-Qaida in the Islamic Maghreb (AQIM). Belmokhtar broke away from AQIM ate last year to form his own group the Signers in Blood.
Nigeri infiltrated Algeria with a group of 40 fighters from Niger, Mauritanian news agency ANI reported.
The group demanded the release of Omar Abdel Rahman, an Egyptian known as "Blind Sheikh" who is imprisoned in the US, and Aafia Siddiqui, a US-Pakistani neuroscientist who was sentenced to 86 years in jail in the US for attempting to shoot her US interrogators after being arrested in Afghanistan.
According to the few details known about him, Nigeri, who is believed to be in his late 30s, joined the Algerian Group for Call and Combat (GSPC) on 2005, which later changed its name to al-Qaida in the Islamic Maghreb.
It is in this group that Nigeri first encountered the Algerian Belmokhtar, a smuggler and jihadi widely reported to be the mastermind of the assault on the In Amenas gas facility.
Belmokhtar appears not to have been present during the raid but Abu al-Bara'a al-Jaza'iri, another leader, is believed to have been shot.
The militants said earlier on Saturday they were holding seven foreign hostages, one Briton, two Americans, three Belgians and one Japanese. A total of about 30 foreigners remain unaccounted for.
The authorities said more than 570 Algerian workers had been freed following a military rescue mission on Thursday and that 100 of 132 foreign contractors taken hostage at the gas field had been rescued or had escaped.
Surviving hostages described scenes of turmoil and terror. Some said the jihadists had killed a number of foreign contractors.