Algeria hostage crisis not over, U.K. warns ALGIERS, Algeria The hostage crisis in the remote desert of Algeria is not over, Britain said Friday, after an Algerian raid on the gas plant to wipe out Islamist militants and free their captives from at least 10 countries unleashed bloody chaos. Algerian helicopters and special forces stormed the complex Thursday, leaving the fate of the fighters and many of the captives uncertain. But Britain's Foreign Office said Friday morning in a statement to CBS News and other news outlets that "the terrorist incident remains ongoing." It said it could give no further details. Dueling claims from the military and the militants have muddied the world's understanding of an event that angered Western leaders. Conflicting claims left Western leaders in the dark and Algeria's government was keeping tight control of information. Deaths and survivors in Algerian hostage rescue At least one American, Mark Cobb, who had hidden in a meeting room, is known to have gotten out of the gas plant, CBS News correspondent Mark Phillips reports. One high-ranking source in the U.S. government told CBS News that four Americans had been freed, one of them injured, after the raid. Prime Minister David Cameron spoke twice to his Algerian counterpart on Thursday, Britain's Foreign Office said. We are not in a position to give further information at this time. But the Prime Minister has advised we should be prepared for bad news," it said. CBS News national security correspondent David Martin reports the U.S. government sent a Predator surveillance drone to the BP-operated site, near the border with Libya and 800 miles from the Algerian capital, but it could do little more than watch Thursday's intervention. The militants - led by a Mali-based al Qaeda offshoot known as the Masked Brigade - suffered losses in Thursday's military assault, but succeeded in garnering a global audience. The militants, via a Mauritanian news website, claimed according to the Associated Press that 35 hostages and 15 militants died in the helicopter strafing. President Obama and Cameron spoke on the phone to share their confusion. White House press secretary Jay Carney said the Obama administration was "seeking clarity from the government of Algeria." Militants earlier said they were holding seven Americans, but the administration confirmed only that Americans were among those taken. The U.S. government was in contact with American businesses across North Africa and the Middle East to help them guard against the possibility of copycat attacks. Jean-Christophe Gray, a spokesman for Cameron, said Britain was not informed in advance of the raid. One Irish hostage managed to escape: electrician Stephen McFaul, who'd worked in North Africa's oil and natural gas fields off and on for 15 years. His family said the militants let hostages call their families to press the kidnappers' demands. At least one Filipino managed to escape and was slightly injured, the Philippine Foreign Affairs Department said. Spokesman Raul Hernandez said he had no information about any fatalities. Algerian Interior Minister Daho Ould Kabila said the 20-odd militants entered the country from nearby Libya in three vehicles, in an operation commanded by extremist mastermind Moktar Belmoktar, who is normally based in Mali. The militants made it clear that their attack was fallout from the intervention in Mali. One commander, Oumar Ould Hamaha, said they were now "globalizing the conflict" in revenge for the military assault on Malian soil. France has encountered fierce resistance from the extremist groups in Mali and failed to persuade many allies to join in the actual combat. The Algeria raid could push other partners to act more decisively in Mali - but could also scare away those who are wary of inviting terrorist attacks back home.