Malaysia has tightened security on its northern border after a bomb exploded in a popular tourist district in southern Thailand, injuring 28 people, including Malaysian visitors, police said.

Police also cautioned local travellers to remain alert when visiting the Muslim dominated south, which had been hit by a string of bomb attacks recently.

"It's better if they visit only if they must and if they suspect anything amiss, they should contact the authorities," Abdul Aziz Nawi, northeastern Kelantan's police chief, was quoted by the official Bernama news agency as saying.

Border checks intensified

The bomb blast on Saturday night in Sungai Golok, a town on the Malaysian border packed with nightspots, karaoke bars and brothels, is the first time the attacks have targeted civilians or tourist districts.

The bomb was placed on a motorcycle near a strip of bars, injuring local residents as well as workers and customers, police said. They were not immediately able to say how many Malaysians were hurt.

About 55 people, including government officials, police and army officers, and even Buddhist monks have been killed in a wave of violence in the south since the beginning of the year.

Abdul Aziz said police would intensify border checks to ensure security and urged the public to remain calm. - AFP