"Cambodia is one of the most significant single sources of weapons for the insurgent group," Jane's Intelligence Review said in a report published online last week, without naming any sources.

Interior ministry spokesman Khieu Sopheak acknowledged Monday that some weapons might still be getting to the Tigers, but said any smuggling would be small-scale.

"There could be some bad people involved.... We would like information to lead us to the offenders," he told AFP.

"We are victims of weapons, so we don't want people in other countries to suffer the same crisis," he said.

Meanwhile, at least five Tamil Tiger guerrillas were killed in fresh fighting with Sri Lankan troops in the island's northwest, the rebels said Monday.

The rebel Liberation Tigers of Tamil Eelam (LTTE) resisted an advance by government forces in Mannar district on Sunday evening, Tiger spokesman Rasiah Ilanthiriyan said in a statement.

"Unable to face stiff retaliation of the LTTE defenders, the Sri Lanka armed forces formation fell back with heavy casualty and material loss," he said.

"After chasing intruders away, the LTTE fighting units are consolidating the positions and searching the area. Five valiant front liners of the LTTE lost their lives in this clash."

There was no immediate reaction from the military.

The latest clash came after the government marked the capture of the final bastion of the LTTE in the east of the island with a victory parade last week.