One Indonesian hostage died in still unclear circumstances when Philippine security forces clashed with Muslim militants who seized three men four months ago.
Mr Heri Ardiansyah, 19, and Mr Hariadin, 45, were rescued on Friday by a unit of marines chasing a small group of terrorists during a clash on Simisa island in the southern province of Sulu, said a statement issued by the Joint Task Force Sulu.
The two hostages and their captors were attempting to swim to another island when they were spotted, according to the statement.
Three militants were killed in the ensuing firefight. Mr Heri was rescued, but Mr Hariadin purportedly drowned.
But in a conflicting account, Colonel Gerry Besana, spokesman for the Western Mindanao Command, told news website BenarNews that the militants shot the two Indonesians, as they were trying to flee from a previous encounter on Thursday.
The third hostage, Malaysian Jari Abdullah, 34, was rescued in that firefight. He was said to have been shot and left for dead by his captors as he tried to escape. He was reported to be in stable condition at a hospital in Zamboanga city.
The Indonesian authorities, however, said the Indonesian hostage who died was caught in the crossfire.
"He was in the position of being surrounded by soldiers and militant groups. He panicked and fled," Mr Lalu Muhammad Iqbal, a director at the Indonesian Ministry of Foreign Affairs, told BenarNews.
The three hostages were taken by Abu Sayyaf militants from their fishing trawler in waters off eastern Sabah, near the Philippines' Tawi-Tawi island chain, on Dec 5 last year.
The two Indonesians were later seen in a video begging for their lives. One of the men had a knife held to his neck.
The small but brutal Abu Sayyaf has pledged allegiance to the Islamic State in Iraq and Syria (ISIS). Though the Philippine group officially has a separatist Islamist agenda, it has capitalised on decades of instability in the war-torn southern island of Mindanao to generate tens of millions of dollars from piracy and ransom payments.
Since it turned kidnapping into a lucrative trade, the group has already beheaded an American, a Malaysian, two Canadians and a German.
A faction led by Isnilon Hapilon took part in the assault on the southern Islamic city of Marawi in May 2017.
Hapilon's fighters, along with those from Marawi's prominent Maute clan and extremists from abroad, stormed and took control of a quarter of Marawi for five months, in what became the Philippines' biggest security crisis in years.
Hapilon was killed as the Marawi conflict drew to a close. But other Abu Sayyaf factions that did not participate in the Marawi siege have remained active in Sulu and in their other stronghold, Jolo.
