The threat of kidnappings by pirates in the Sulu Sea is rising, warns the International Maritime Bureau (IMB).
The sea between eastern Malaysia and the Philippines is a stronghold of Abu Sayyaf, an al-Qaeda linked terror group responsible for seizing seafarers, particularly from tugs and barges.
Armed men have attacked a fishing boat, killing eight fishermen, in an apparent pirate attack off the southern Philippines this week.
"The kidnapping of crew from ocean going merchant vessels in the Sulu Sea and their transfer to the Southern Philippines represents a notable escalation in attacks," Kuala Lumpur-based IMB said.
IMB is advising charterers and owners to consider avoiding the Sulu Sea by routing vessels west of Kalimantan.
Piracy down overall
In its annual report, IMB said piracy attacks were at their lowest level since 1998, but more crew had been abducted in 2016 than at any time over the last decade.
A total of 150 vessels were boarded globally, with 12 fired on and seven hijacked.
Pirates seized 151 people as hostages.
Indonesian piracy incidents fell to 49 in 2016 from 108 in 2015
IMB also said the Gulf of Guinea in Africa remains a kidnap hotspot.
Peru recorded 11 incidents last year, against none in 2015.
