Seafarers have been warned to maintain a sharp anti-piracy watch off Indonesia's war-torn Aceh coast after eight attacks on ships within four months, the International Maritime Bureau (IMB) said today.

"We are putting out a red alert to all ships entering the Malacca Strait: Keep clear of Indonesia's Aceh coast and maintain strict anti-piracy watch," Noel Choong, the Malaysian-based IMB regional director told AFP .

"Ships are advised to sail closer to the Malaysian coast."

The Malacca Strait, a narrow waterway slicing Indonesia's sprawling Sumatra island from Malaysia, is one of the busiest shipping lanes in the world, funnelling 50,000 vessels a year between the biggest economies of the West and the East.

Under fire

Choong said that since May, armed pirates had attacked eight ships off the Aceh coast, including a Nowegian LPG (liquid petroleum gas) carrier and an Indian oil tanker.

"Their modus operandi is to come close in three boats and try to stop the ship. In some attacks, they sprayed bullets at the ships to stop the vessels," he said.

Choong said in all these attacks, the ships managed to sail on.

In the latest attack on Saturday the captain of a Taiwanese fisheries ship, the 3,000-tonne "Dong Yih", was wounded when his vessel was fired on as it headed for Singapore.

An official from Taiwan's National Rescue Command Center said: "The two pirate ships were disguised as oil rig tug boats... that was why the captain did not pay attention to them when they showed up."

Asked who could be behind the attacks, Choong declined comment but one industry analyst who requested anonymity said it could be Aceh rebels who have been fighting for independence since 1976.

"It is likely to be Indonesia's Aceh rebels who require funds to buy weapons," he said.

Dangerous spot

The analyst said while there was no evidence to prove their involvement, the military style approach and the automatic weapons used pointed to the Aceh rebels.

In other attacks off Indonesia's coast, pirates were usually lightly armed, he noted.

The IMB in July said piracy on the international high seas surged 37 percent to an all-time high of 234 attacks from January to June this year, leaving 16 seafarers dead.

Indonesian waters were the most dangerous, "accounting for over one quarter of the world total with 64 incidents." - AFP