JAKARTA (AFP) - Ten Indonesian sailors have been kidnapped in Philippine waters by Islamic militants who have demanded a ransom for their release, a minister said Tuesday.
The crew were travelling on two boats that were transporting coal from Borneo island to the Philippines when they were hijacked, said Indonesian Foreign Minister Retno Marsudi.
It is not clear when the vessels - a tugboat and a barge - were hijacked but the boats' owners received a ransom call from someone claiming to be from the Abu Sayyaf militant group on Saturday, she said.
The Philippine military said they had heard reports the sailors may have been taken by an Abu Sayyaf faction to one of their hideouts in the conflict-wracked south, but were still working to get confirmation.
Abu Sayyaf is a Philippines-based Islamist group notorious for bombings and kidnappings, which has pledged allegiance to the Islamic State group.
Their most recent high-profile kidnapping was of two Canadians and a Norwegian from yachts at a marina in September, with the militants setting an April deadline for millions of dollars in ransom money to be paid.
In the latest case, Marsudi said the hijackers had contacted the boats' owners twice since Saturday and had sought a ransom, but refused to say how much was demanded.
"Our priority is the safety of the 10 Indonesians who are being held hostage, we will keep working hard to save them," the minister told reporters, adding she had been in touch with her Philippine counterpart.
It is unclear where the barge Anand 12 and the crew are being held by the kidnappers but the tugboat Brahma 12 had been released to the Philippine authorities, she said.
Major General Demy Tejares, deputy commander of a task force overseeing southern islands in the Philippines, said authorities were working to confirm the kidnapping had occurred.
He said initial information from sources on the ground indicated the sailors may have been taken by an Abu Sayyaf faction to Sulu, a remote island in the country's southwestern tip that is a hideout of the militant outfit.
He said the tugboat had been recovered on nearby island Tawi-Tawi and was being held by police.
Abu Sayyaf, which operates from remote jungle bases in the southern Philippines, was founded in the 1990s with the help of late Al-Qaeda mastermind Osama bin Laden.
It has been blamed for a string of attacks, including the deadliest in the nation's history, the 2004 Manila Bay ferry bombing that claimed more than 100 lives.
A US-assisted campaign against the militants launched around a decade ago was considered a success, with many Abu Sayyaf leaders arrested or killed.
But recent kidnappings, including of the Canadians and Norwegian, in areas previously considered beyond the group's reach, have raised new fears.
Last year the militants beheaded a Malaysian man after abducting him from a seaside restaurant in Malaysia's Sabah state.
A Malaysian woman seized along with him was released after a ransom was reportedly paid.
The Philippine government has repeatedly said it has a "no-ransom policy". But parties linked to foreigners held hostage by the Abu Sayyaf often pay to win their release.
In October 2014 the Abu Sayyaf claimed it received 250 million pesos (S$7.3 million) in exchange for two German hostages it held captive for six months. Security analysts said a large ransom was paid.