Philippines terror group Abu Sayyaf has killed a seafarer seized from a Vietnamese bulker in February.

The crewman died as the gunmen were escaping from troops in Tawi-Tawi three weeks ago, the Concord Register reported.

Cirilito Sobejana, commander of the joint task force in Sulu, confirmed the death, adding that five seafarers remain hostages.

Another crewman was killed in the attack on the 4,700-dwt Giang Hai (built 2010) off Borneo on 19 February.

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