MANILA - Gunmen kidnapped two Canadian tourists, a Norwegian employee and a Filipina from a luxury resort island in the conflict-wracked southern Philippines, while other foreigners narrowly escaped, police said Tuesday.

The abductions add to a string of kidnappings of foreigners in the south since the early 1990s, most often by Islamic militants seeking to extort ransoms, although the latest culprits were not immediately identified. Police said armed men sailed two motorboats into a marina on Samal island just before midnight on Monday and seized the four from aboard yachts, apparently knowing exactly who they wanted to abduct, police said.

"They appeared to target the foreigners. They went straight for the yachts," Superintendent Antonio Rivera, a local police spokesman, told AFP. He said a Japanese couple was also nearly abducted but the pair fought back, while some of the more than two dozen guests jumped into the water to escape. Law enforcement boats and helicopters were scouring the waters around the island on Tuesday to try to stop the kidnappers from leaving the area, according to Rivera, but they appeared to have escaped. "We still don't have anything. We're blank. No group has taken responsibility and there is no demand for ransom."

A police report identified the Canadian tourists as John Ridsdel, 68, and Robert Hall, 50. The Norwegian, who was working at the marina, was identified as Kjartan Sekkinstad, 56. The 40-year-old Filipina, identified only as Tess, was a companion of one of the foreign tourists, Rivera said. The Canadian and Norwegian embassies in Manila declined to comment. A Norwegian foreign ministry spokeswoman in Oslo, Lothe Salvesen, confirmed to AFP that one of its citizens had been abducted in the Philippines, but gave no further details. President Benigno Aquino, who was at the resort last week for a meeting with political allies, was monitoring developments and authorities were doing their best to find the captives, his spokesman told reporters.

"The investigation is in full swing, simultaneous with pursuit operations," spokesman Herminio Coloma said. Samal island, a short boat ride from the southern commercial centre of Davao on Mindanao island, is famed for powdery white sand beaches and dive spots, with resorts there charging up to $500 a night.

The area, about 800 kilometres (500 miles) southeast of Manila, is a popular stop for foreign tourists who sail around the nation's many tropical islands.

But the Philippines' southern region has endured decades of conflict, with Muslim rebels waging a separatist conflict that has claimed tens of thousands of lives. Parts of Mindanao are also home to more extreme Muslim militants, the most infamous of which is the Abu Sayyaf.

The Abu Sayyaf is a ragtag group of several hundred men founded in the 1990s that has withstood US-backed military operations to extinguish it. They have engaged in frequent kidnappings of locals as well as foreigners in often successful efforts to extort ransoms. They are also blamed for the nation's worst terrorist attack, the 2004 bombing of a ferry in Manila that claimed more than 100 lives.

In their most recent kidnapping of foreigners, Abu Sayyaf gunmen seized a German couple in April last year while they were sailing off the far southwestern island of Palawan, a popular tourist destination. The couple was released six months later, with the Abu Sayyaf claiming it had received all of the 250 million pesos ($5.4 million) it demanded in ransom.

The Abu Sayyaf is currently holding four other foreigners -- a Dutch man, a Korean and two Malaysians, according to the military. In April 2000, the group seized 21 European and Asian tourists in a daring cross-border raid on the Malaysian diving resort of Sipadan. All were freed one year later. In May the following year, the group seized 20 people from the Dos Palmas beach resort in Palawan, including an American missionary couple and a compatriot who was eventually beheaded.

The most recent Abu Sayyaf attack on Samal happened in 2001, when militants raided the Pearl Farm resort on an islet 15 minutes by boat from the main island. No hostages were taken but the attack left two resort workers dead and three others wounded.