Malaysia triggered a potential diplomatic row with India when a senior minister on Friday threatened Tamil Nadu Chief Minister M Karunanidhi that he should "lay off" after the Dravida Munnetra Kazhagam leader voiced concern over the harsh police action against ethnic Tamils in the country.

The comments by Nazri Aziz, Minister in the Prime Minister's Department, came even as the US supported the Tamils while underscoring the rights of Malaysians to hold peaceful protests.

In a strong response to Karunanidhi's statement that he was "very pained" over the treatment meted out to Tamils, Aziz said he should "worry" about his own state which has problems and not about the happenings in Malaysia.

"His place is in Tamil Nadu, not Malaysia. He should worry about his own state. His own state has got problems," Aziz was quoted as saying by the local media.

"This has got nothing to do with him ... lay off," he was quoted as saying by the New Straits Times.

Karunanidhi had on Tuesday said he was  "very much pained" at the way in which Tamils in Kuala Lumpur were treated by the Malaysian police on November 25, when they organised a rally in protest against the "marginalisation of the ethnic Indian minority in that country".

A US State Department official, meanwhile, commenting on the crackdown of unprecedented street protests told AFP, "We believe citizens of any country should be allowed to peacefully assemble and express their views."

The US official, speaking on condition of anonymity, did not go beyond his succinct statement, which was the first reaction by Washington on the rare outpouring of anti-government dissent in Malaysia.