The fate of "fewer than 10" British nationals caught up in the Algerian hostage crisis remains unknown as the four-day stand-off in the desert came to a bloody climax.
Foreign Secretary William Hague said that while the large majority of Britons at the BP gas plant at In Amenas were now safe, the country needed to be prepared for more "bad news".
"As of now there are fewer than 10 British nationals at risk or unaccounted for. But that of course means that we continue to prepare ourselves bad news," he said.
The Algerian state news agency, APS, reported that seven hostages died as Algerian special forces mounted a "final assault" on the last terrorists holding out at the sprawling gas facility. Eleven of the militants were also reported to have died in the shoot-out.
Mr Hague, who chaired a meeting of the Government's Cobra emergencies committee, said he had spoken to the Algerian foreign minister but made no mention of Saturday's fighting.
"This whole incident underlines the scale and ruthlessness of the terrorist threat that we and other nations face," he said. "We underline our resolve to deal with that and to defeat terrorism and murder, working with allies across the world, including in north Africa."
He said that a consular team was now on the ground in In Amenas providing assistance to those Britons who had escaped while the ambassador Martyn Roper was travelling to the area.
The situation at the plant remained unclear, with reports that 16 foreign nationals - including two Americans, two Germans and a Portuguese - had been freed.
APS quoted an Algerian security source as saying that the hostages who died had been killed by their captors.
Earlier, the kidnappers - who call themselves the Masked Brigade or "The Signers in Blood" - told a Mauritanian news agency they are in contact with that they were holding seven foreigners - one British, three Belgians, two Americans and one Japanese.