COLOMBO, June 18: Sri Lanka’s police said suspected Tamil Tiger rebels killed three policemen in an ambush in the island’s north on Sunday, while the Tigers said government forces had attacked them elsewhere.

If government estimates are correct that 25-30 Liberation Tigers of Tamil Eelam (LTTE) rebels were killed in a naval clash on Saturday, more than 100 people have died since Thursday, the worst violence since a 2002 ceasefire halted two decades of war.

Police Deputy Inspector General Gamini Silva told Reuters that a police water tanker was attacked with a claymore fragmentation mine near the northern town of Vavuniya, just south of rebel territory. He blamed the Tigers.

“There were only three policemen,” he said. “It was a claymore attack. They were all killed.”

In a later incident in the same district, gunmen fired on government troops before escaping, he said. A military source said the army was looking for two missing soldiers.

Some 700 people have died so far this year, Nordic ceasefire monitors say, almost all of them since early April.

Claymore fragmentation mine attacks, artillery duels, government air strikes and naval battles have become increasingly common.

A suspected Tiger mine attack on a civilian bus in north central Sri Lanka on Thursday killed 64 people from the island’s Sinhalese majority, prompting the heaviest government air strikes on rebel areas in the north and east since the truce.

Tiger eastern political leader Daya Mohan said fighters from breakaway ex-rebels and police Special Task Force troopers fired four or five shells and small-arms across the front line in the island’s east on Sunday.

The Tigers accuse the government of backing fighters led by former eastern rebel commander Karuna Amman and using them to mount attacks on the mainstream rebels.

The government denies it, but some diplomats are increasingly sceptical.

“We retaliated with heavy fire and they vanished from the scene,” Mohan told Reuters.