AP

JAKARTA, Indonesia (AP) — Indonesia's foreign ministry said Tuesday that 10 Indonesian nationals are being held hostage after their ship was hijacked in Philippine waters.

The ministry said in a statement that the owner of the hijacked tug boat and coal barge has received two telephone calls, purportedly from militant group Abu Sayyaf, demanding a ransom.

It does not know exactly when the incident occurred but said the ship owner was first contacted on Saturday. The ministry's statement also referred to the hostage takers as pirates.

"The current priority is the safety of 10 citizens who were taken hostage," the statement said. It said the company that owns the ship has informed the families of the crew.

Abu Sayyaf, which is on U.S. and Philippine lists of terrorist organizations, is notorious for bombings, extortions and kidnappings for ransom in the volatile south of the Philippines. It has been weakened by years of U.S.-backed Philippine offensives but remains a security threat.

The tug, Brahma 12, and the Anand 12 barge were going from Sungai Putting in Kalimantan, which is the Indonesian part of Borneo island, to Batangas in the southern Philippines.

Philippine police say the tug boat was found in Languyan town in the southernmost Philippine province of Tawi Tawi. Indonesia's foreign ministry believes the barge carrying about 7,000 tons of coal is still under the control of the hostage takers.

Philippine security officials suspect the al-Qaeda-linked Abu Sayyaf for last year's abductions of two Canadians, a Norwegian and a Filipino woman from a marina on southern Samal Island. The kidnap victims are believed to be held in the jungles of southern Sulu province.

In a recent video posted on a Facebook account linked to the militants, they threatened to kill the hostages unless a huge ransom was paid by April 8. The Philippine military said the government's no-ransom policy remains and security forces would continue efforts to secure the safe release of the captives.

Indonesia has been helping the Philippines forge a peace agreement with Filipino Muslim rebels by sending soldiers to join an international oversight group which helps monitor government and rebel adherence to a cease-fire.