The Sri Lankan military has begun an investigation into how a Tamil Tiger suicide squad infiltrated an air force base on Monday.
At least nine members of the security forces were killed at the base at Anuradhapura, 210km (130 miles) north of Colombo, as well as 20 rebels.
Two rebel planes also flew overhead and dropped bombs.
Meanwhile the army says 15 rebels were killed later on Monday in clashes on the front lines further north.
The rebels said 21 of their fighters, among them women, destroyed eight aircraft including spy planes in the attack at Anuradhapura.
The Tigers' leader and the fighters said to have taken part in the raid
The military said just two helicopters and a training plane were damaged.
As well as the nine military personnel killed at the base, four more airmen died when their helicopter sent to provide back-up crashed in the area.
The attackers were wearing uniforms similar to Sri Lankan air force fatigues although the Tigers have insisted they broke none of the rules of war.
The military said the bodies of 20 Tamil Tigers had been found.
On Tuesday their bodies were displayed naked in the town as they were taken to Anuradhapura hospital mortuary.
Military spokesman Brigadier Udaya Nanayakkara said the rebels must have cut through the perimeter fence because they would have been challenged at the gate.
He also dismissed reports that troops may have been distracted in the hours before the battle by a popular talent show on television.
Meanwhile the government has announced a re-organisation of command in the area.
Maj Gen Sanath Karunaratne has been given overall responsibility for all security and civilian administration in the region.
On Tuesday the military said that there was another clash later on Monday in which 15 Tamil Tigers were killed in the northern Vavuniya region.
The Tigers spokesman, Rasiah Ilanthiriyan, said the military was trying to spread false propaganda.
He said they had suffered only two wounded in the Vavuniya fighting.
The BBC's Roland Buerk in Colombo says fighting in the north has escalated in recent weeks ahead of a possible government offensive to take rebel-held areas.