A joint panel has been formed to investigate the theft of diesel oil from a Thai tanker by a group of suspected pirates in the waters off Pahang last Friday.

National Police deputy spokesman Col Krissana Pattanacharoen said the joint panel comprised representatives from the Marine Police and Army.

"The investigation into the incident is ongoing and the nationality of the pirates and whether any Thai was involved in the heist is unclear," he was quoted by the local media today.

However, he said the six or seven pirates who boarded the tanker communicated in Bahasa.

The tanker identified as 'CP14' and owned by a Thai company was sailing to Songkla in southern Thailand from Singapore about 9pm when it was alleged that six or seven pirates boarded the ship in waters off Pahang.

The pirates tied up the 17 crew members, including the captain and destroyed the Ship Security Alert System before siphoning the 1.5 million litres of diesel from the total 3.8 million litres the tanker ferried.

Yesterday, the Commander of Royal Thai Navy Second Naval Base, Vice-Admiral Pornchai Pinthong said the incident occurred in Malaysian waters at Latitude 03.55.27 and Longitude 103.52.81.

The Royal Thai Navy has also informed the Malaysian authorities of the incident and requested its assistance to pursue the alleged pirates.

Pornchai said the tanker continued its journey to southern Thailand after the incident and arrived in waters off Songkla, two days ago.

The navy despatched a warship, HTMS Takbai to check on the tanker and its crew.

-- BERNAMA