Indonesia has the most dangerous waters for international shipping, a global watchdog has reported.

There were 44 pirate attacks in Indonesian waters and nine more in the nearby Strait of Malacca, accounting for nearly one-third of the 171 incidents recorded by the International Maritime Bureau (IMB) in the first six months of this year.

Armed pirates in speedboats and gunboats open fire on ships and rob or hijack them

International Maritime Bureau

Attacks around the world have risen by 3.6% compared with the same period in 2001 with India, Bangladesh and the southern part of the Red Sea being named as other hotspots.

Captains were also warned to stay at least 100 miles off the coast of Somalia amid lawlessness which has turned the risk of pirate attack by armed militia "from one of possibility to certainty", according to the bureau's Piracy Reporting Centre.

Sailors killed

In the first six months of 2002, six crew members were killed in attacks worldwide - four of them in Indonesian waters, said a report from the centre, which is based in Kuala Lumpur.

Pirates use guns and knives to overpower crews

Another 21 people were injured and 23 crew members are listed as missing.

Most pirate attacks are robberies of cargo, the contents of ships' safes or crew members belongings.

But in the January-June period, 14 vessels had been hijacked to extort money from owners for the return of the vessel and crew - two more than in the same period last year, the report said.

Crude methods

Pirates' methods remained generally crude, with knives being the weapons of choice in 57 of the attacks and guns in 31.

Indonesia's 44 attacks were the same number as in the first six months of 2001.

Incidents fell slightly in India - from 13 to 12 - and Bangladesh - from 15 to 11.

Targets

General cargo ships Bulk carriers Oil tankers

The IMB said increased numbers of sea patrols had helped, though the waters remained dangerous.

Outside Asia, the worst-affected country was Nigeria with eight acts of piracy, compared with six from January to June 2001.

Most of the attacks took place on the open seas, but near Somalia there was also danger closer to land from armed militia groups.

"Armed pirates in speedboats and gunboats open fire on ships and rob or hijack them," the piracy centre said.

"Any vessel which slows down or stops close to the Somali coast will be boarded by these gangs who have so far been successful in extorting substantial sums from owners for the return of the vessel and the crew," it added.