COLOMBO: Sri Lankan troops killed 18 Tamil Tiger rebels during ground and air assaults on their northern mini-state, the defence ministry said Sunday.

One solider was also killed during the heavy fighting that broke out on Saturday just outside the Tiger's political capital of Kilinochchi, the ministry said in a statement.

The fighting raised the number of rebels killed by troops since January to 7,404 as the military closes in on the rebels' mini-state. Some 733 soldiers have died in the same period.

Casualty figures cannot be verified as the ministry blocks journalists from travelling to the frontlines.

There was no immediate comment from the Liberation Tigers of Tamil Eelam (LTTE), who have been fighting for a separate state for ethnic minority Tamils since 1972 in a drawn-out conflict that has killed thousands.

Having wrested the east from the Tigers in July 2007, troops are just outside the northern Kilinochchi, which has been the LTTE's administrative centre for the past decade.

Sri Lanka pulled out of a six-year Norwegian-brokered truce in January and has poured in a record 1.5 billion dollars into this year's war effort in an attempt to defeat the rebels.