MANILA -- A Vietnamese hostage has been killed during a gunbattle between his captors and government troops that also left four bandits and a soldier dead in Mindanao, a military official said Thursday.

Brigadier General Cirilito Sobejana said troops found the body of Viet Van Tran after the fighting Saturday, July 8, in the jungles of mountainous Patikul town in Sulu province, where ransom-seeking Abu Sayyaf bandits are holding several Filipino and foreign hostages.

"There are two possible scenarios. It's either he was hit during the fighting or he tried to escape while taking advantage of the situation and was shot by some of his abductors," Sobejana told reporters.

The victim was one of six Vietnamese crewmen abducted by the bandits in an attack on their cargo ship in February. He was the latest Vietnamese hostage to be killed in recent weeks while in Abu Sayyaf custody, Sobejana said.

Two Vietnamese crewmen from a separate group abducted by Abu Sayyaf gunmen in an attack on their cargo ship last November in the south were found beheaded last week on the southern island of Basilan, where the brutal group also has had a long presence.

Another Vietnamese who was kidnapped along with the two slain crewmen escaped from his captors in Basilan in June. Three other Vietnamese remain captive, the military said.

President Rodrigo Duterte and his Malaysian and Indonesian counterparts have struggled to deal with a wave of attacks by the Abu Sayyaf and allied gunmen who have targeted tugboats and cargo ships along their busy sea borders in recent years.

The alarming kidnappings have eased after the three countries took steps to strengthen their border security, including coordinated maritime patrols that were launched last month. A US Navy ship and a Philippine frigate also completed four days of coordinated patrols in the area early this month. (AP)