Two Southeast Asian seafarers kidnapped last month in the Malacca Straits by armed pirates believed to be Indonesians have been freed, officials said today.

"The two - a Malaysian captain and Indonesian chief officer - were released yesterday," Noel Choong, regional manager of the Piracy Reporting Centre of the International Maritime Bureau, told AFP .

Choong said they arrived at Port Klang, west of Kuala Lumpur, on a fishing boat from Indonesia.

Their tugboat was attacked by gun-wielding pirates on Feb 28 in what is said to be the first incident since the deadly December tsunamis.

Pirates shot the chief engineer in the leg and kidnapped the other two.

Maritime patrols

The ship was towing a coal-laden barge and heading towards Lumut in northern Perak state where Malaysia's naval base is located.

Choong renewed the call to Malaysian and Indonesian authorities increase maritime patrols in the Malacca Straits to stop the attacks.

The waterway bordered by Malaysia, Singapore and Indonesia is used by some 50,000 ships a year carrying a third of world trade and half its oil supplies.

Thirty mariners were killed worldwide last year in pirate attacks including four in the Malacca Straits, the Piracy Reporting Centre said in its annual report last month.