BAMAKO, Mali — Without warning other governments, Algeria mounted an assault on Thursday on the heavily armed fighters holding American and other hostages at a remote Sahara gas field facility, freeing captives and killing kidnappers but leaving some hostages dead and foreign leaders scrambling to find out the fates of their citizens.
Almost a day after the raid, there was no official word on Friday on the number of hostages who had been freed, killed or still held captive. Estimates of the foreign casualties ranged from 4 to 35, though one Algerian official said the higher figure was “exaggerated.”
In London on Friday, British officials said the Algerian authorities had not informed them that the military operation deep in the Sahara had been concluded. Until the British heard otherwise, one official said, speaking in return for anonymity, “we are working on the basis that it’s an ongoing operation.”
The official declined to comment on widespread reports that British authorities were bracing for high casualty figures among up to 20 Britons thought to have been working at the installation. French officials said on Friday that there had been “very few” French nationals at the site and at least two of them were safe.
Algeria’s reported silence about the situation on the ground seemed to deepen frustration among foreign governments with citizens who had worked at the plant, close to the Libyan border.
On Thursday, despite requests for communication and pleas to consider the safety of their abducted citizens, the United States, Britain and Japan said they had not been told in advance about the military assault, stirring frustration that the Algerians might have been overly aggressive and caused needless casualties.
But the Algerian government, which has a history of violent suppression of Islamist militancy, stood by its decision to deal forcefully with the kidnappers, who were holding Algerians and citizens of nine other countries.
“Those who think we will negotiate with terrorists are delusional,” the communications minister, Mohand Saïd Oublaïd, said in an announcement about the assault on the facility near In Amenas, in eastern Algeria, close to the Libya border. “Those who think we will surrender to their blackmail are delusional.”
The midday assault came more than 24 hours after a militant group, which the Algerians said had ties to jihadis in the region, ambushed a bus carrying gas-field workers to a nearby airport and then seized the compound. It was one of the boldest abductions of foreign workers in years.
The abductions were meant to avenge France’s armed intervention in neighboring Mali, Mr. Oublaïd said, a conflict that has escalated since French warplanes began striking Islamist fighters who have carved out a vast haven there.
On Thursday, the United States became more deeply involved in the war, working with the French to determine how to best deploy American C-5 cargo planes to ferry French troops and equipment into Mali, according to an American military official.
The United States has long been wary about stepping more directly into the Mali conflict, worried that it could provoke precisely the kind of anti-Western attack that took place in Algeria, with deadly consequences. After the raid to free the hostages, the Algerians acknowledged a price had been paid.
“The operation resulted in the neutralization of a large number of terrorists and the liberation of a considerable number of hostages,” said Mr. Oublaïd, the communications minister. “Unfortunately, we deplore also the death of some, as well as some who were wounded.”
Algerian national radio described a scene of pandemonium and high alert at the public hospital in the town of In Amenas, where wounded hostages and those who escaped were sent. The director of the hospital, Dr. Shahir Moneir, said in the report that wounded foreign hostages were transferred to the capital, Algiers.
In a telephone interview from the hospital, an Algerian who escaped, who identified himself as Mohamed Elias, said some of the hostages had exploited the chaos created by the Algerian assault to flee. “We used the opportunity,” he said, “and we just escaped.”
Senior American military officials said that aides traveling in London with Defense Secretary Leon E. Panetta were struggling to get basic information about the raid, and that an unarmed American Predator drone was monitoring the gas-field site.