The rebel Liberation Tigers of Tamil Eelam (LTTE) said the attacks were aimed at provoking them and asked the Scandinavian-led truce monitors to investigate the attacks and make the findings public.

The LTTE said Monday's attacks against three of their women political activists in the island's eastern province could not have been carried out without the backing of security forces.

"We fear that such attacks could result in far-reaching consequences on the three-year long ceasefire agreement," the LTTE said in a statement Wednesday.

"Such attacks are clearly intended to provoke the Tamil people and the LTTE, who maintain severe restraint despite having lost senior officials and cadres to such traitorous attacks during the period of ceasefire."

Also Monday, a former government soldier was shot dead in the same province and the military accused the Tigers of involvement.

The state-run Daily News reported Wednesday that the president had decided to appoint two high court judges to probe the violence and report within a month.

"The president has further directed that investigations should be made as to whether any group or groups of terrorists or any other forces in the Eastern province are involved in these attacks," the newspaper said.

There was no immediate comment from the president's office.

The violence was seen as a further blow to the already faltering Norwegian-brokered peace process.

Talks between Colombo and the Tigers have been on hold since April 2003 but both sides have pledged to uphold an Oslo-arranged ceasefire in place since February 23, 2002.