Investigators were working "around the clock" to find five Europeans linked to the British embassy but no one has claimed responsibility for their disappearance or made any demands, officials said Tuesday. The five Europeans were in a tour group, which included 13 Ethiopian drivers and translators, that went missing Thursday while traveling in Ethiopia's Afar region, a barren expanse of salt mines and volcanoes 800 kilometers northeast of the capital, Addis Ababa. "We're working around the clock to secure their safe return," a British Foreign Office spokesman in London said on condition of anonymity in line with ministry policy. He said no one has claimed responsibility. A British embassy official in the Ethiopian capital, also speaking on condition of anonymity because of embassy policy, echoed that and added that no demands had been made. The five are employees of the British Embassy in Addis Ababa, or their relatives. Diplomatic officials have said all are Britons, but French Foreign Minister Philippe Douste-Blazy said Tuesday that one of them is French.