Malaysia put its border police on alert and warned citizens against crossing into southern Thailand today after six protesters died in the latest clash with Thai security forces in the troubled region.

Police had been instructed to step up security to prevent Thai militants from taking refuge in Malaysia, said Zuber Shariff, police chief of the border state of Kelantan.

Zuber, quoted by the official Bernama news agency, warned Malaysians to avoid crossing into southern Thailand, a popular tourism and shopping destination.

Foreign Minister Syed Hamid Albar expressed concern about Monday's violence in which six demonstrators died when security forces broke up a day-long protest by up to 3,000 people outside a police station.

"The flare-up in southern Thailand is a matter of concern to us. Thailand is a close neighbour. Any incidents will be watched closely here," Syed Hamid said.

Sad about incident

The fighting was sparked by the arrest of six Muslim men accused of handing guns to rebels in Muslim-majority southern Thailand, where an insurgency has left more than 330 people dead this year.

Mainly Muslim Malaysia was working closely with Thailand to develop the troubled south so that economic prosperity would bring peace to the region, Syed Hamid said.

Thai Prime Minister Thaksin Shinawatra hosted talks with Malaysian Prime Minister Abdullah Ahmad Badawi earlier this month to flesh out development plans for the three southernmost Thai provinces.

"We are sad there has been an incident. We will wait and see what had happened," Syed Hamid said.