By Roland Buerk BBC News, Colombo

	PM has expressed 'regret' over evicting Tamils from Colombo

Sri Lanka's Government is trying hard to defuse criticism at home and abroad over the expulsion of ethnic minority Tamils from the capital.

The Prime Minister Ratnasiri Wickremanayake said the Government regretted the police operation to round up nearly four hundred people and drive them away under armed guard, ostensibly to their home villages.

International condemnation

He said it was a mistake and would not happen again.

Ministers had at first vigorously defended the move.

	Rights watchdogs staged a protest in the capital, Colombo

They said it was necessary to prevent infiltration of the capital by the Tiger rebels, who are fighting for a homeland for the Tamil minority.

But human rights groups called it collective punishment, the United States led the international condemnation and the Supreme Court issued an order preventing any more expulsions.

Protest against eviction

Tamil and left wing political parties along with trade unions and human rights organisations staged a protest in the capital, Colombo, against eviction.

Many of those forced to leave have since been allowed to return.

The Prime Minister's role is largely nominal - it's the President Mahinda Rajapakse who's in charge in Sri Lanka.

He's ordered an immediate explanation of the incident from the country's top police officer, and promised disciplinary action if there is any evidence of wrong doing.