Police in Sri Lanka have forced hundreds of minority ethnic Tamils out of the capital, Colombo, for what they say are security reasons.

Police launched pre-dawn raids Thursday in Tamil areas of the city, forcing ethnic Tamils staying in budget hotels onto buses. Police say Tamils who were in Colombo without what they called "valid reasons" were made to board buses bound for the north and east of the country. Local human rights groups have condemned the evictions as "ethnic cleansing."

Meanwhile, a top Japanese envoy visited eastern Sri Lanka to meet civilians displaced by fighting between Tamil rebels and government forces.

Yasushi Akashi toured camps Thursday in Batticaloa district and met with officials involved in resettling their residents. The envoy is in Sri Lanka to try to stop a recent upsurge in fighting and persuade the two sides to return to negotiations.

Violence between government forces and Tamil rebels has killed about 4,000 people in Sri Lanka in the past 18 months.

Norway brokered a ceasefire in 2002 that has been violated repeatedly by both sides, though neither has renounced it.

Tamil rebels have been fighting for independence in the northern and eastern areas of the island nation since 1983.

Some information for this report was provided by AFP and AP.