Wednesday 23 April 2014 03.58 BSTJapanese ship boarded in Malacca Strait and diesel pumped into waiting vessels before raiders fled taking three crew with them.

Armed pirates raided a Japanese oil tanker in the Malacca Strait, pumping out much of its cargo and taking three crew away, Malaysian maritime police have said.

Six pirates in a speedboat boarded the Naninwa Maru 1 at 1am local time on Wednesday off the coast of west Malaysia, said Abdul Aziz Yusof of the maritime police.

The pirates pumped out more than half of the 5m litres of diesel carried by the tanker into two waiting vessels and left taking three crew members with them. Domestic media said the crew taken away were Indonesians.

The Japanese tanker had been headed for Burma from Singapore and had Indonesian, Thai, Burmese and Indian crew members.

Regional security officials have previously said armed gangs working the Malacca Strait may be part of a syndicate that can either have links to the crew on board the hijacking target or inside knowledge about the ship and cargo. Such hijacks involved seizing tankers and stealing petroleum cargo to be sold on the black market.

Attacks by gangs armed with guns and knives on shipping in the Malacca Strait ranged from 12 to 20 incidents a year over the last three years, according to the Singapore headquarters of the Regional Co-operation Agreement on Combating Piracy and Armed Robbery against Ships in Asia (Recaap). Most of these incidents involved the theft of ship's stores, cash and assaults on the crew.

A peak of 220 recorded attacks took place in 2000, according to the Kuala Lumpur-based International Maritime Bureau, which tracks pirate activity.

The Malacca Strait carries about a quarter of the world's seaborne oil trade.