Colombo: Sri Lankan troops killed 52 Tamil Tiger rebels in weekend fighting in the island's north while seven soldiers died, the military said on Monday, as the 25-year-old civil war escalates.

The fighting in several northern districts came amid near daily land, sea and air attacks, as the government pursues a strategy to gradually retake the Tigers' northern stronghold and win the protracted civil war.

"Troops killed 33 Liberation Tigers of Tamil Eelam terrorists in Sunday's fighting," said a military spokesman, adding that five soldiers also died from the fresh fighting.

The military also said 19 rebels and two soldiers were killed in fighting on Friday and Saturday, and more than 100 rebels and 40 soldiers injured in weekend fighting.

The Tigers, who want to create an independent state in north and east Sri Lanka for ethnic Tamils, a minority in predominately Sinhalese Sri Lanka, were not immediately available for comment.

Pro-rebel website www.tamilnet.com, quoting Tiger rebels, said they had put up stiff resistance to military attempts to advance into rebel-held areas in the far north on Sunday.

"Eighteen Sri Lanka Army soldiers were killed. More than 31 SLA soldiers were wounded in the confrontations," the website said.

"Heavy fighting, backed by heavy artillery and mortar barrage, continued ... when the ground movement of the SLA was thwarted."

The government and rebels trade death toll claims that are rarely possible to independently verify.

Nordic truce monitors, who blamed troops and rebels for repeated abuses, were banished by the government after President Mahinda Rajapaksa formally scrapped a 6-year truce in January.

Analysts say the military has the upper hand in the latest phase of the long-running war given superior air power, strength of numbers and swathes of terrain captured in the island's east. But they still see no clear winner on the horizon.

An estimated 70,000 people have died since the civil war began in 1983.

The Tigers are regularly hitting back with suicide attacks increasingly targeting civilians and roadside bombs, experts and the military say, which have deterred some tourists and worried some investors in the $27 billion economy.