COLOMBO, Oct 5 (Reuters) -- Thousands of Sri Lankans who fled to Colombo in the past five years lined up to register on police orders on Sunday, part of a government security drive to keep Tamil Tiger rebel infiltrators out of the capital city.

Those told to register with the authorities on Sunday left the Eastern Province, where the separatist Liberation Tigers of Tamil Eelam (LTTE) had controlled large swathes until being ejected last year by the army and a breakaway rebel faction.

"It is going smoothly," police spokesman Senior Superintendent of Police Ranjith Gunasekara said.

The Supreme Court turned down an attempt to stop the drive by a rights group, which complained the exercise was unfairly targeting Tamil people. The court upheld it as a voluntary registration.

A similar drive two weeks ago went off smoothly. It involved people who had fled the Northern Province, which is almost entirely populated by Tamil people. The east is more mixed.

Rights groups have warned that the drives could deepen the distrust between Tamils living in the capital of the Indian Ocean nation and the security services, which draw most of their personnel from the Sinhalese majority.

Tamils complain of regular harassment.

The registration comes as the military took its war with the Tamil Tiger rebels right to the edge of the rebel's headquarters town in the north. Many fear an increase in bomb attacks in the city as the guerrillas grow more cornered.

The Tamil Tigers, on U.S., European and Indian terrorism lists, have fought one of Asia's longest-running insurgencies to establish a separate homeland for Sri Lanka's minority Tamils.

Since independence from Britain in 1948, the island nation has been ruled by governments led by the majority Sinhalese people, who are 75 percent of Sri Lanka's 21 million population. (Reporting by Ranga Sirilal; Writing by Bryson Hull; Editing by Valerie Lee)

AlertNet news is provided by