The air of uncertainty over the future of Sri Lanka's Norwegian-backed truce with the Tamil Tiger rebels had increased due to the slaying of Foreign Minister Lakshman Kadirgamar, main opposition leader Ranil Wickremesinghe said Sunday.

Addressing a public gathering of his United National Party (UNP) held in the northwestern town of Puttalam, Wickremesinghe praised the services of Kadirgamar who was gunned down by suspected Tamil Tiger gunmen at his private residence late night on Friday.

"He believed in peace negotiations to solve the ethnic problem, " Wickremesinghe said.

In a statement issued Saturday, the UNP said the assassination "will have a serious impact on the already fragile Ceasefire Agreement."

The Liberation Tigers of Tamil Eelam (LTTE) has been fighting for an independent state since 1972 in a conflict that has claimed over 60,000 lives. Norway brokered a truce in 2002, but talks between the two sides have stalled since April 2003.

The LTTE denied involvement in the killing but the statement was rejected by the government.

The political party leaders represented in Parliament met under the chairmanship of Prime Minister Mahinda Rajapakse to condemn the killing of a man described by Sri Lankan President Chandrika Kumaratunga as "a hero of our times."

Police chief Chandra Fernando said that some 18 people had been arrested for suspected involvement in the murder.

Military Spokesman Brigadier Daya Ratnayake said that entry from the rebel held areas into government controlled areas in the north and east was restricted on Sunday as part of the manhunt for the killers.

The security forces have been told to step up random checks of vehicles and property, Ratnayake added.

Source: Xinhua