Before the incident, Aswadi and three colleagues had stopped a Thai man in a pickup truck from entering Malaysia at a border checkpoint in northern Kedah state, suspecting him of being involved in diesel smuggling.

The disgruntled driver had left but returned shortly afterwards with reinforcements, who chased the border officials, the newspaper said.

"We had a tip-off that they were returning to attack us. So we quickly ran to my car, which was at the parking lot. But it was too late. The gang spotted us," Aswadi was quoted as saying.

"I tried to fight off my attackers with one of their bats," he added.

After the melee, the Thais fled from the checkpoint back to their country with customs officials in pursuit on foot.

Aswadi's three colleagues managed to escape the gang and alerted security guards at the checkpoint.

Malaysia border officials and police said they were investigating the incident.

Malaysian fuel subsidies mean prices are still low compared with the rest of the region, tempting smugglers to sell diesel in neighbouring Thailand, where it is more expensive.

Agence France-Presse