BAMAKO, Mali — Officials said Sunday that the death toll from the four-day hostage siege at a natural gas-producing complex in the Algerian desert had passed 80, as security forces combing the site discovered more corpses, some badly burned.
The Algerian government said at least 25 more bodies were found Sunday morning, though it was unclear whether they were militants or hostages because they were so disfigured.
Officials also said at least seven American hostages were found safe and five militants were captured, contrary to earlier reports that all the militants had been killed.
Algeria had said after Saturday’s assault on the complex by security forces that at least 32 extremists and 23 hostages were killed. On Sunday, bomb squads sent in to blow up or defuse explosives found the additional bodies, the Associated Press reported, citing a security official who spoke on condition of anonymity.
“I’m very afraid that the numbers are going to go up,” the Algerian communications minister, Mohamed Said Belaid, told France 24 Television.
Hundreds of Algerian and scores of expatriate workers were employed at the facility deep in the Sahara. The dead hostages were from the United States, Britain, France, Japan, and other countries. More than two dozen foreigners were unaccounted for Sunday, including at least one American.
The confrontation at the remote gas field taken over by militants was brought to an end Saturday as the Algerian Army carried out a final assault. The details of the desert standoff and the final battle for the plant remained murky.
But some new details emerged Sunday. The attackers were a multinational group from six countries, Belaid told the official APS news agency. He would not identify the countries by name, but other senior officials said that there were indications that the group originated in northern Mali and was once linked to Al Qaeda in the Islamic Maghreb, Al Qaeda’s North African branch.
In a statement, the Masked Brigade, which claimed to have planned the takeover, warned of more such attacks against any country backing France’s military intervention in neighboring Mali, where the French are trying to stop an advance by Islamic extremists, the AP reported.
‘‘We stress to our Muslim brothers the necessity to stay away from all the Western companies and complexes for their own safety, and especially the French ones,’’ the statement said.
The group, which is based in Mali, is commanded by an Algerian jihadist, Moktar Belmoktar, who claimed direct responsibility for the attack through spokesmen. Algeria also blamed him for the attack.
The fighting began with heavy gunfire early Wednesday, and continued through a fierce, helicopter-led government assault on Thursday. Most of the hundreds of workers at the plant, who came from about 25 countries, appeared to escape sometime during the four days. The complex is operated by BP, Statoil of Norway, and Sonatrach, the Algerian national oil company.
The total number of people who were held hostage remained unclear Sunday. There was also some questions about the aggressive tactics used by the Algerian Army. Western leaders have criticized the Algerian government for failing to consult them before the military action.
Survivors’ accounts of the takeover and the army’s raid were harrowing. Some hostages who managed to escape told of workers being forced to wear explosives. They also said that there were several summary killings and that some workers had died in the military’s initial rescue attempt.
Alan Wright, a British survivor, said in an interview with Sky News that he spent two days hiding in an office complex with 30 workers listening to sounds of gunfire outside.
The majority, he said, were Algerian citizens who he said could have left him and his colleagues. Instead, he said, they helped them escape by dressing them as locals and cutting through several perimeter fences. They were rescued by Algerian soldiers.
“I can’t say enough about the guys in our building, who had the option to surrender and be safe,” he said. “You’ll be in debt to them for the rest of your life.” He also praised the Algerian military: “If it weren’t for them, I think it would have been a lot worse.”
David Plouffe, a senior adviser to President Obama, said Sunday that Al Qaeda and Al Qaeda-affiliated groups remain a threat in North Africa and other parts of the world and that the US is determined to help other countries destroy those networks.
Western leaders called for a decisive and far-reaching response to the attack, indicating a willingness to expand military operations in North Africa to counter deeply rooted Islamist militant groups.