COLOMBO (AFP) - Norway's peace envoy Erik Solheim failed to secure agreement today with Tamil Tigers on a truce and negotiations as violence escalated killing at least 12 security personnel, officials and rebels said.

Solheim travelled to an area held by the separatist Liberation Tigers of Tamil Eelam (LTTE) to finalise a ceasefire and other measures to open direct negotiations with the government, but returned without agreement.

"No agreement was reached at this discussion," the LTTE said in a two-page statement issued shortly after Solheim left the rebel-held Wanni region and headed for the capital Colombo.

The Norwegian embassy here declined to comment on the LTTE statement but said Solheim was due to hold meetings with President Chandrika Kumaratunga and an opposition politician before leaving Sri Lanka shortly.

The LTTE said they agreed with Solheim to keep up their deliberations at a later date, but did not say when the next round of talks with Solheim will take place.

But they insisted they would not talk to the government unless a ban on the group is lifted.

Government ban

The government ban was introduced in January 1998, immediately after an LTTE suicide bomber attacked the holiest Buddhist temple in the central town of Kandy, with devastating results.

The rebels said they also wanted Colombo to completely lift economic sanctions and agree to a permanent truce.

"These are not demands or preconditions for talks but rather pre-requisite necessary steps to create the very foundation for political negotiations," the LTTE statement said.

It added that the lifting of the ban on the LTTE had become the "major hurdle" for opening talks which Norway has been trying to broker for the past two years.

Meanwhile, official sources said a total of 12 security personnel, including a constable, were killed in three attacks on today in the Vavuniya district, 260 kilometres north of the capital.

Hours before Solheim crossed the front lines there, the rebels set off a powerful land mine killing one soldier.

As Solheim reached Vavuniya before travelling back to Colombo, there were two more rebel attacks against the army and the police in the area.

In one attack at Chettikulam, seven soldiers were killed and several more wounded in a mine blast. The defence ministry said four soldiers died and another 14 were wounded, but other sources said seven troopers had died.

Solheim's visit had been delayed by a day after a mine attack deep inside the guerrilla-controlled Kokkavil area on Tuesday, which killed one rebel.

The LTTE accused a "deep penetrating unit" of the security forces for carrying out that attack.

Latest statement

In their latest statement, the Tigers denied they were delaying the peace process.

"It is wrong to assume the LTTE is deliberately procrastinating the peace talks," the LTTE said. "We have always insisted that we cannot participate in peace negotiations while engaging in a bloody war."

The group said their campaign was unique and they should not be compared to the Irish Republican Army, the Palestinian Liberation Organisation or rebel groups in northeast India.

The lifting of the ban on LTTE was the central issue taken up with Solheim during the talks, the rebel radio said earlier today.

They also discussed a memorandum of understanding and a ceasefire, the Voice of Tigers said.

Earlier, the sticking point was a truce, with the rebels insisting on a formal ceasefire and the government calling for an informal de-escalation process.

Britain banned the LTTE in February in line with its new anti-terrorism laws. The US listed the LTTE as a foreign terrorist group in October 1997.

India banned the LTTE after the group emerged as prime suspects in the assassination of former Indian prime minister Rajiv Gandhi in May 1991.