WASHINGTON, Jan 17 (Reuters) - The White House said on Thursday it believed Americans were among the hostages taken by militants at an Algerian gas plant, was concerned about reports of deaths in an operation by Algerian forces and was seeking more information.
"This is an ongoing situation and we are seeking clarity," White House spokesman Jay Carney said when asked about the Algerian military operation to end the desert siege. President Barack Obama was being briefed regularly by his national security team, he said.
Carney said the U.S. government was still trying to determine the number of casualties and who they were, and was also in touch with British Petroleum officials in London. BP operates the gas field, together with Norway's Statoil and Algeria's state company Sonatrach.
Twenty-five foreign hostages escaped and six were killed on Thursday when Algerian forces launched an operation to free them at the remote desert gas plant, Algerian sources said, as one of the biggest international hostage crises in decades unfolded.
Three other hostages were later freed by the army, a local source told Reuters, as the military operation continued.
The standoff began when Islamist gunmen stormed the gas facility on Wednesday. They said they were holding 41 foreigners and demanded a halt to a French military operation against fellow al Qaeda-linked Islamist militants in neighboring Mali.
Details of the military operation to free the hostages from the gas plant were difficult to confirm.
"The best information we have at this time ... indicates that U.S. citizens are among the hostages, but we don't have at this point more details to provide to you," Carney said, condemning the hostage taking as a "terrorist attack."
Asked whether the Americans involved were dead or alive, Carney said, "I just can only say that we are deeply concerned about any loss of innocent life and are seeking clarity from the government of Algeria."
He said it was premature to say whether Algeria consulted with Washington before the hostage rescue mission. "Our priority is determining the status of the Americans involved and getting a full understanding of what took place," he said.
Carney said the Algerian crisis was not expected to affect U.S. deliberations on providing logistical support to French forces that have intervened in Mali to fight Islamist rebels.
"We share .... the French goal of denying terrorists in Mali a safe haven -- denying terrorists in the region a safe haven," he said. He said U.S. authorities were working with the French "to provide them support in moving troops and equipment."
Carney said the United States had no immediate confirmation of al Qaeda links to the hostage taking in Algeria and Washington was trying to find out what group was behind it.