(UPDATED) Two hostages in Sulu were freed by abductors, the government said on Saturday.
The victims were identified as South Korean ship captain Chul Hong Park and Filipino second officer Glenn Alindajao.
The two were the only ones abducted from 20-crew ship Dong Bang Giant on October 20 last year, as other crew members were able to hide after they were caught by armed men aboard a speed boat in the waters off Tawi-Tawi.
The ship was on its way to South Korea from Australia when the incident occurred.
Dureza said he informed President Rodrigo Duterte through presidential assistant Bong Go about the release.
In a press briefing, Dureza said they could not yet tell if abductors belonged to Islamic State (ISIS)-affiliated Abu Sayyaf Group (ASG).
However, he revealed that the hostages were released with the help of the Moro National Liberation Front (MNLF).
Dureza said there were 27 hostages abducted through the years by kidnap-for-ransom groups, including the Abu Sayyaf group.
Around 27 hostages are still being held in Sulu by abductors who include members of the Abu Sayyaf Group.
Park and Alindajao said they were frequently moved to different places in Sulu by their abductors so that the military could not trace their location.
Dureza said the hostages planned to escape, but their attempt did not push through as there was an "enabling environment" in the area which were favorable for the abductors.
Some communities in Sulu were allegedly tipping off the abductors as to the movements of Philippine government forces.