Manila - Gunmen holding three foreigners and one Filipina hostage have slipped past a naval cordon and escaped to remote mountains in the southern Philippines without making ransom demands, police said Wednesday.
Elite army troops were trying to track the bandits while air force helicopters were readied for a possible rescue as the abductors trekked into Davao Oriental province, a hotbed of Maoist and Islamic rebels, said Senior Superintendent Aaron Aquino, the region's deputy police commander.
The gunmen seized two Canadian tourists, a Norwegian employee and a Filipina from a luxury island resort on Monday night, adding to a string of kidnappings of foreigners in the conflict-wracked south since the 1990s.
"Last night, we received information that the kidnappers and their victims have been sighted... they are in the Davao Oriental area," Aquino told DZBB radio.
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"Our scout rangers are following their tracks. They are on their trail. The air force is also helping, ready for insertion."
Police and the navy had tried to set up a boat blockade on Tuesday around Samal island, where the four were abducted, to stop the gunmen escaping on their outriggers.
But Aquino's comments confirmed the abductors had slipped past and sailed about 50 kilometres (30 miles) east to Davao Oriental, a poor farming and fishing region on the far southeastern edge of Mindanao island.
Canadian tourists John Ridsdel, 68, and Robert Hall, 50, were among those abducted, police said.
The other foreigner was Norwegian resort employee Kjartan Sekkinstad, 56, and the local woman was Hall's 40-year-old Filipina girlfriend, identified only as Tess.
It was not clear which group was behind the abductions.
"We are waiting for contact from the kidnappers so we will know their demands," Aquino said.
Investigators were looking at the possible involvement of communist guerillas or Islamic rebels excluded from a peace treaty signed in 2014 with the government, according to Aquino.
Communist and Islamic rebels have been waging decades-long struggles that have claimed tens of thousands of lives.
The impoverished regions of Mindanao have proved fertile recruiting grounds and sanctuary for both groups.
However Aquino said he doubted the involvement of the Abu Sayyaf, an Islamic militant group infamous for carrying out dozens of kidnappings-for-ransom of foreigners as well as locals since the early 1990s.
The outriggers used to storm the marina on Samal island at midnight on Monday were not a "signature" of the Al-Qaeda-linked group, because they typically have high-speed boats, he said.
Nevertheless, armed bandits have in the past kidnapped foreigners in Mindanao and sold them to the Abu Sayyaf.