Pirates reportedly boarded a Japanese oil tanker carrying five million litres of diesel early yesterday, siphoning off part of the cargo and kidnapping three Indonesian crew-members.

At last eight masked men, said to be armed with pistols and parangs, hijacked the ship in the Straits of Malacca, 21.8 nautical miles off the coast of Tanjung Karang, Selangor, according to New Straits Times today.

Marine Police Zone 1 Commander Mohd Yusof Abdullah was quoted as saying the pirates had boarded the vessel using a speed boat at 1am.

“The pirates started pumping diesel from the tanker into their boat. They took three Indonesian crew-members and the crew’s belongings and identification documents, before fleeing,” he reportedly said.

However, Yusof said it is unclear how much of the fuel was stolen.

The Star quoted Port Klang Marine Police Commander Norzaid Muhammad Said as saying that two tankers had approached the hijacked vessel and siphoned off three million litres of diesel.

"They (pirates) fled about five or six hours later," he said.

Norzaid said the 18 crew-members were tied up during the raid but were able to free themselves several hours after the pirates left.

"The crew-members comprised Indonesian, Thai, Myanmar and Indian nationals. But the Indonesians were nowhere in sight. We suspect that they have been kidnapped ...," he was quoted as saying.

He added that the ship has since anchored and the authorities are investigating the matter.