A state of emergency was imposed in Sri Lanka on Saturday, hours after the assassination of foreign minister Lakshman Kadirgamar, suspected to have been carried out by Tamil Tiger rebels.
"A state of national emergency has been declared to facilitate enhanced security measures and effective investigations of this act of wanton terror," President Chandrika Kumaratunga's office said in a statement.
"The President appeals for calm and restraint in the face of this grave and cowardly attack upon Sri Lanka," it said.
The announcement came after the assassination of 73-year-old Kadirgamar, a Tamil Christian and native of Jaffna who led the efforts to ban the Liberation Tigers of Tamil Eelam as a terrorist outfit, late last night.
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He was shot several times on the head and chest at his heavily-guarded home by suspected rebel snipers.
He was rushed in a critical condition to the National Hospital, where he died. The emergency gives security forces sweeping powers to arrest and detain suspects for long periods.
Defence Ministry spokesman Daya Ratnayake has asked Colombo residents to remain indoors on Saturday to allow a major search operation to go ahead.
He said the Tamil Tigers were the prime suspects in the slaying but the authorities were working with an 'open mind.'
"We strongly suspect the Tigers because he had threats from the LTTE," Ratnayake said. "Two weeks ago too, we arrested 2 suspected LTTE men who had been spying on the minister."
Kumaratunga's spokesman Eric Fernando said the state of emergency would last for an indefinite period.
The killing of Kadirgamar, a close confidante of Kumaratunga, has dealt a heavy blow to the shaky peace process in the island nation.
Hagrup Haukland, the chief of Norway's truce monitors, said the assassination was a 'big, big blow to the ceasefire and the whole peace process irrespective of who is behind this.'
Erik Solheim, a top Norwegian peace broker, described the killing as a 'major setback' for the peace process.
The Oxford-educated foreign minister, who was shot between 10 pm and 11 pm on Friday night and succumbed to his wounds at 12:15 am, had attended an official function and driven back to his private home for a swim when he was attacked, officials said.
Kadirgamar, born on April 12, 1932, was the most senior Sri Lankan leader to be assassinated since a bomb attack killed President Ranasinghe Premadasa in May 1993.
He was one of the most tightly-guarded ministers in Sri Lanka and had nearly 100 elite bodyguards deployed to protect him.
Kadirgamar was strongly opposed to the campaign for separation led by the LTTE and was also a critic of the Norwegian-led peace process in the island nation.
He, however, maintained that the conflict must be resolved peacefully.
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Sri Lankan armed forces have launched a helicopter search for assailants. Police said they found spent ammunition near the scene.
In her statement, Kumaratunga hailed Kadirgamar, who is survived by wife Suganthie and two children - Ragi and Ajitha, as a 'national hero' who waged "a relentless struggle against
terrorism in all its forms, despite continuous threats to his life."
Kumaratunga blamed the killing on "political foes opposed to the peaceful transformation of conflict and who were determined to undermine attempts toward a negotiated political
solution to the ethnic conflict."
The President was herself seriously wounded in an assassination attempt in 1999. Police blamed Tamil Tiger rebels for that attack, which killed 26 people.