COLOMBO, August 3, 2008 (AFP) - At least 21 Tamil rebels and a Sri Lankan soldier were killed in clashes in the island's north, the defence ministry said Sunday.

The fighting, which occurred on Saturday in several parts of the north, included naval troops killing four rebels and destroying one guerrilla boat around the government-controlled Jaffna peninsula.

The figures raise to 5,496 the number of rebels killed by troops since January, while 496 soldiers have died in action over the same period, according to a tally of the defence ministry's daily claims.

There was no comment from the rebels. Casualty claims from either side cannot be verified since the ministry blocks journalists from visiting the front lines.

The Liberation Tigers of Tamil Eelam had offered a unilateral ceasefire to coincide with a two-day South Asian Association for Regional Cooperation (SAARC) leaders' summit that began in Colombo on Saturday.

The government, however, brushed off the offer and has stepped up attacks against rebel positions in the north.

The Tigers have been fighting for a separate Tamil homeland in the majority Sinhalese nation since 1972.