A search has failed to find two European birdwatchers a day after they were abducted by armed men on an island in the south of the country, authorities said today. Regional military spokesman, Lieutenant Colonel Randolph Cabangbang said marines dispatched to rescue Dutchman Ewold Horn, 52, and Swiss national Lorenzo Vinzigueere, 47, had so far failed to find the two men. “There is a massive search-and-rescue operation right now to find the kidnappers and their captives,” he said. Citing initial reports, Cabangbang said the two Europeans were with a Filipino guide when they were seized by the group in the village of Parangan, in the Tawi Tawi islands. The kidnappers “grabbed the victims and dragged them to the beach where a boat was waiting,” Cabangbang added. The guide, Nestor Cabaluas, who managed to escape the kidnappers, said the Europeans were on an expedition to photograph rare hornbills on the islands, which are in the Sulu Sea. It is yet unclear who was behind the kidnapping but Islamic militants, including Abu Sayyaf, have been blamed for a series of kidnappings in the south since 2010, including an Australian citizen who was abducted in Zamboanga Sibugay on December 5. The kidnappings prompted the United Kingdom to warn its citizens today against traveling to parts of southern Philippines. In its travel advisory for the Philippines, the UK Foreign and Commonwealth Office cited a "threat from kidnapping in the Philippines, particularly in the south." Foreigners have been targeted in rural, urban and coastal areas in the past, it added.