Hostage siege at Algeria gas plant not over 18 January 2013 Last updated at 10:40 The hostage crisis at a gas facility in the Algerian desert has yet to be resolved, officials have said. The UK said the incident near In Amenas was "ongoing" and Algerian state media said Islamist militants were holding foreign workers at a treatment plant. At least four hostages and a number of militants were killed on Thursday when troops stormed the living quarters. The militants had claimed to be holding 41 foreigners. At least four were freed but the fate of many others is unknown. We deeply regret the actions taken by the Algerian military End Quote Yoshihide Suga Japanese Chief Cabinet Secretary Algeria has yet to give precise casualty figures from the rescue attempt. The state-run APS news agency cited local officials as saying two Britons and two Filipinos were killed. Two others, a Briton and an Algerian, died on Wednesday when the militants ambushed a bus that was taking foreign workers at the facility to the local airport. A spokesman for the militants told the Mauritanian ANI news agency that 35 hostages and 15 militants had been killed by helicopter gunfire in Thursday's operation. The In Amenas gas field is operated by the Algerian state oil company, Sonatrach, along with the British oil company BP and Norway's Statoil. It is situated at Tigantourine, about 40km (25 miles) south-west of the town of In Amenas and 1,300km (800 miles) south-east of Algiers. Hiding under bed On Friday morning, the UK Foreign Office and Norwegian Foreign Minister Espen Barth Eide said they believed the incident was ongoing. UK Foreign Secretary William Hague condemns "the wanton act of terrorism" in Algeria Parts of the plant are under Algerian authorities' control, and other parts are not. This information is changing by the hour," Mr Eide told the BBC. Later, APS cited local officials as saying the military operation at the gas facility's living quarters, where most of the hostages were held, had ended on Thursday night. "Hostages are still being held at the Tigantourine gas treatment plant, which is surrounded by special forces," APS added. UK government sources said they were trying to establish the fate of a number of British people and were bracing themselves for multiple casualties. Foreign citizens involved Fourteen Japanese missing Eight Norwegians missing Unspecified number of Britons missing; two Britons (from Scotland) believed to be safe Unknown number of Americans Possibly citizens of Romania, Thailand, the Philippines, Colombia, South Korea and Austria Two French citizens safe One Irish citizen from Northern Ireland safe One Kenyan safe Prime Minister David Cameron is chairing a meeting of the cabinet emergency committee, Cobra, and is expected to update Parliament on the situation shortly. Japanese officials were meanwhile cited as saying by the Kyodo news agency that at least 14 Japanese nationals were still missing. At least three managed to escape. Japan's Chief Cabinet Secretary, Yoshihide Suga, expressed "deep regret" at the actions of the Algerian security forces and its foreign ministry summoned the Algerian ambassador. Norwegian Prime Minister Jens Stoltenberg said the Algerian officials had said "they felt they had no choice but to go in." Norway said eight of its nationals were currently unaccounted for. One is being treated at a hospital in In Amenas, while four escaped unharmed. French Interior Minister Manuel Valls said two French workers were safe. It was unclear if another two were involved, he added. Ireland's Deputy PM described hostage Stephen McFaul's escape as a "truly horrific" experience Five Americans had survived and left the country, US officials told ABC News. APS said about 600 local workers had been freed in the raid, but many were reportedly allowed to leave on Wednesday by the militants. A worker from CIS Catering, which employs about 150 Algerians at the facility, told French media he had hidden under the bed in his room for 40 hours before being rescued. I put boards everywhere. I had food, water, and I did not know how long I would stay there. When the soldiers came to get me, I did not even know it was over. They were with colleagues, otherwise I would never have opened the door," he added. A statement purporting to come from the kidnappers says the raid was carried out in retaliation for the French intervention against Islamist groups, including al-Qaeda in the Islamic Maghreb (AQIM), in neighbouring Mali. But BBC security correspondent Gordon Corera says the kidnapping was a complex operation which is unlikely to have been planned and carried out since the surprising French intervention in Mali last Friday. Algerian Communications Minister Mohand Said Oubelaid said the militants were intent on "destabilising Algeria, embroiling it in the Mali conflict and damaging its natural gas infrastructure." Algerian officials said they were operating under orders from Mokhtar Belmokhtar, who was a senior AQIM commander until late last year. On Friday morning, a spokesman for al-Mulathameen (The Brigade of the Masked Ones) told ANI that it would carry out further operations. He warned Algerians to "stay away from the installations of foreign companies as we will strike where it is least expected."