Sri Lanka's main opposition said the move was similar to what Hitler did to the Jews in the early days in Germany.
President Mahinda Rajapakse demanded an explanation from police Inspector General Victor Perera for forcing Tamils out of their sleep and bussing them 260 kilometres (160 miles) north of Colombo to a detention centre.
"The president has called for an explanation from the IGP," an official at the president's office said.
"He has also ordered measures to redress the injustices during yesterday's police action.
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The presidential orders went out after the Supreme Court halted the evictions and the United States, a key ally of the government, led international condemnation of Thursday's events.
Police sources said they were trying to undo the damage by arranging five buses Friday evening to bring back to Colombo the Tamils who were forcibly removed from low-budget hostels.
"Out of 272 held at the Vavuniya centre, we are bringing back 186 in the next few hours," a police