COLOMBO : Sri Lankan troops killed 28 Tamil rebels and seized a cache of weapons and ammunition in their latest push for victory in the island's drawn-out ethnic conflict, the government said Thursday.

Security forces captured nine mortar tubes from a fortified camp at Kuppilankulam on Wednesday, the defence ministry said in a statement, adding 28 Tamil Tiger guerrillas had been killed in fighting in the area.

Also seized were a workshop for making hand grenades and roadside bombs, and several vehicles including an armour-plated van used by Tiger leader Velupillai Prabhakaran, the ministry said.

Military officials have speculated that Prabhakaran may have slipped out of the country by boat as his fighters have been pushed into a narrow patch of jungle.

The government has said it will crush the rebels shortly and end the decades-long armed campaign for an independent Tamil homeland.

Concern has mounted for thousands of non-combatants trapped in the war zone and the International Committee of the Red Cross has said that hundreds of civilians have been killed in crossfire this year.

The ICRC said Thursday it planned to evacuate 160 patients from a makeshift hospital where artillery fire killed 16 people earlier in the week.