ALGIERS, Algeria— An Algerian military raid to free hostages from at least 10 countries at a remote Sahara natural gas complex and wipe out their Islamist militant captors unleashed bloody chaos, and the British government said Friday that the situation was not yet over.The fate of the fighters and many of the captives remained uncertain, and dueling claims from the military and the militants have muddied the world’s understanding of an event that angered Western leaders.By nightfall, Algeria’s government said the raid was over. But Britain’s Foreign Office said Friday morning that "the terrorist incident remains ongoing.” It said it could give no further details. Manuel Valls, France’s interior minister, said the situation remained murky.At least six people, and perhaps many more, were killed — among them Britons, Filipinos and Algerians. Terrorized hostages from Ireland and Norway trickled out of the Ain Amenas plant. Dozens more remained unaccounted for: Americans, Britons, French, Norwegians, Romanians, Malaysians, Japanese, Algerians and the fighters themselves."This remains a fluid and evolving situation and many details are still unclear, but the responsibility for the tragic events of the last two days squarely rests with terrorists who chose to attack innocent workers, murdering some and holding others hostage,” British Foreign Secretary William Hague told Sky News from Australia.Algeria’s army-dominated government, hardened by decades of fighting Islamist militants, shrugged aside foreign offers of help and drove ahead alone, keeping a tight control of information even to Western leaders.On Friday, Algeria’s ambassador to Japan was summoned by the senior vice minister of foreign affairs, who demanded that Algeria prioritize hostages’ lives and cooperate closely.British Prime Minister David Cameron spoke twice to his Algerian counterpart on Thursday and was "prepared for bad news,” Britain’s Foreign Office said.A U.S. official said late Thursday that while some Americans escaped, other Americans remain either held or unaccounted for. The official spoke on condition of anonymity because he wasn’t authorized to discuss the matter publicly.The U.S. government sent an unmanned surveillance drone to the BP-operated site, near the border with Libya and 800 miles (1,290 kilometers) from the Algerian capital, but it could do little more than watch Thursday’s intervention.With the hostage drama entering its second day Thursday, Algerian security forces moved in, first with helicopter fire and then special forces, according to diplomats, a website close to the militants, and an Algerian security official. The government said it was forced to intervene because the militants were being stubborn and wanted to flee with the hostages.The militants — led by a Mali-based al-Qaida offshoot known as the Masked Brigade — suffered losses in Thursday’s military assault, but gar