Five men, two of them armed with pistols and one with a machete, siphoned off two million litres of diesel from a Japanese vessel about 16 nautical miles from Pulau Ketam here yesterday, marine police said.

It is learnt that in the 1am incident, the robbers also abducted three of the 18 crew of the ship which was on its way from Singapore to Myanmar with five million litres of the fuel.

Port Klang Marine Police commanding officer DSP Norzaid Muhammad Said said the robbers siphoned off the fuel from two tankers, taking between seven and eight hours to do so, after tying up the crew including the captain.

"They then left the ship," he said.

Norzaid said the captain, after freeing himself, informed the diesel supplier in Singapore of the robbery.

The supplier lodged a report at the Johor Baharu police station which relayed the information to the marine police in Port Klang, he said.

"We sent our personnel to the location and found the Japanese vessel at Pulau Angsa. The ship was brought to the North Port here for further investigation," he said.

Norzaid said the captain and crew remaining on the vessel did not suffer any injury.