COLOMBO, Sri Lanka - A rebel kamikaze attack on Sri Lanka's capital could have destroyed the air force but didn't because the two explosives-packed planes were shot down before reaching their targets, the government said Sunday.

The defiant air raid Friday night showed the Tamil Tiger rebels retained the ability to launch paralyzing attacks across the country even with their ground forces under siege in a small patch of territory in the northeast.

The attacks targeted the national air force headquarters and an air base, government authorities said.

"If they (the attacks) really worked, there wouldn't have been an air force," government spokesman Keheliya Rambukwella told reporters.

The two planes were hit by anti-aircraft fire. One crashed into a tax office building near the air force headquarters and exploded, while the second plane was downed near the air force base north of Colombo, authorities said. Four people died, including the two pilots.

Air force spokesman Wing Commander Janaka Nanayakkara said one of the planes was loaded with about 210 kilograms of explosives, but the pilot could not detonate it because he had lost a hand to anti-aircraft fire.

In the northern war front, the government has taken or destroyed about 90 per cent of the rebels' facilities, Rambukwella said. The military says it has captured rebel bomb factories, submarines, diving equipment and large amounts of weapons.

Rambukwella said the two rebel aircraft destroyed Friday night are believed to be the last in the insurgents' tiny air wing.

"It's a great victory against terrorism," he said.

However, the government had also said two weeks earlier that it had disabled the rebels' air capability, making Friday's air raid an embarrassment.

Meanwhile, a pro-rebel Web site published a letter reportedly written by one of the suicide pilots before he set off on the mission. It called on ethnic Tamil youths to join the Tigers in their fight for an independent state for the ethnic minority.

"We have enough armaments. We urgently need manpower," pilot I. Rooban wrote, according to the TamilNet site.

"While we march with explosives inside the lion's den, let's show the strength of Tamil people. I have never dreamed of wasting one's precious life," he wrote. "However, I feel privileged and proud that I can become a Black Tiger to earn respect for my people and my homeland."

Rebel suicide bombers known as Black Tigers have carried out hundreds of attacks against political, military and economic targets since the civil war began in 1983.

More than 70,000 people have been killed in the fighting.

Also Sunday, the military said the number of civilians killed by suspected rebels in an attack on an ethnic Sinhalese village Saturday had risen to 14.

The slayings raised concerns that the rebels, who were driven from their eastern stronghold two years ago by the government, still retained the ability to carry out deadly guerrilla attacks in the area.