The release of four Indonesian sailors by the Abu Sayyaf militant group involved intensive efforts by the government and allegedly involved the paying of a ransom.

On the heels of the sudden release, an anonymous source told thejakartapost.com that the National Intelligence Agency (BIN), the Indonesian Military (TNI), the Coordinating Political, Legal, and Security Ministry and the Foreign Ministry coordinated with the sailors' employer.

“The sailors’ employer paid the ransom,” the source said.

President Joko “Jokowi” Widodo announced earlier that the four remaining Indonesians held captive by the Abu Sayyaf militant group in the Philippines had been released safely.

The Indonesian sailors, kidnapped by the militant group in April, are now in the hands of the Philippine authorities and will be handed over to the Indonesian government soon, Jokowi said at the State Palace as reported by kompas.com.

He gave no further details regarding the release.

The four sailors had been employed as crew aboard the Henry, a tugboat, and the Christie, a barge, sailing in Malaysian and Philippine waters in mid-April when they were taken hostage by the Abu Sayyaf group.

Earlier this month, Abu Sayyaf militants freed 10 Indonesian crewmen who were seized at sea in March and believed to have been taken to a jungle camp in Sulu, a predominantly Muslim province about 950 kilometers south of the Philippine capital, Manila.