Gun-wielding pirates attacked a Malaysian tugboat and kidnapped three of its crew members in the Sulawesi Sea close to Philippine waters, police and officials said today.

Five gunmen, armed with assault rifles, boarded the boat in Malaysian waters off Semporna in Sabah before fleeing towards the southern Philippines with the boat's captain and two crew, a district police spokesman told AFP .

"We believe the kidnappers could be from the Abu Sayyaf," he said.

Abu Sayyaf is a Muslim extremist group in the Philippines notorious for kidnappings for ransom. It has been linked by the United States and the Philippines to the al-Qaeda network.

No ransom demand

The Malaysian-owned Bonggaya 91 was on its way back to Sandakan in Sabah from Indonesia when it was attacked at around 11:00am local time on Wednesday, its owner Vincent Chang told AFP .

The gunmen seized the boat's radio communication set and mobile phones, said Chang, director of Syarikat Pengangkutan Bonggaya.

"Luckily one of my crew hid his mobile phone and was able to call me," he said.

"He said they had been attacked by the Abu Sayyaf. We have no idea how true this is. I immediately notified the police."

The gunmen abducted the tugboat's captain and three crew members, all of whom are Indonesian, he said. No ransom demand had been made, he added.

The remaining crew members arrived in Sandakan on earlier today.