(Updates death toll)

By Ranga Sirilal and Simon Gardner

COLOMBO, March 27 (Reuters) - A Tamil Tiger suicide bomber tried to blow up an army camp in Sri Lanka on Tuesday, killing nine people a day after rebels carried out their first air strike since fighting erupted in 1983.

The military said troops shot the suicide bomber as he tried to drive an explosives-laden tractor into the camp in the eastern district of Batticaloa, setting off an explosion which killed him, three soldiers and five civilians, and wounded 13 others.

The military responded to the attacks with a second consecutive day of air strikes across Tiger-held territory, saying it had destroyed artillery and mortar positions, but there were no immediate details of any casualties.

"We suspect there were more than 200 kg (440 lbs) of explosives (in the tractor)," said military spokesman Brigadier Prasad Samarasinghe. "You can't find even a piece of the trailer. If it had come into the camp, it would have been a major disaster."

The Liberation Tigers of Tamil Eelam (LTTE) were not immediately available for comment on Tuesday's attack.

The military is still investigating how the Tigers managed to fly a light aircraft over the capital undetected, drop bombs and fly back to their northern stronghold without being shot down -- their first such raid since the civil war began.

The rebels claimed to have knocked out 40 percent of the air force's strike capability, but the military said none of its fighter jets targeted by the rebels were damaged in the strike. Nordic truce monitors say they have not had access to the area.

The Colombo Stock Exchange fell 1.3 percent on Monday and another 0.4 percent on Tuesday as the air raid worried investors.

TIGERS VOW MORE ATTACKS

The Tigers said more such attacks by its air wing would follow, threatening to deepen renewed conflict in the island state off the toe of India. The government aims to destroy all rebel military assets, but says the door to resume peace talks remains open -- which the rebels laugh off.

The civilian airport, 23 miles (37 km) north of the capital, next door to the air base was not damaged in Monday's attack but was closed for several hours. Cathay Pacific has suspended inbound and outbound flights.

"The fact that they have acquired air capability, even with a single aircraft a suicide bomber can go in, is a threat to the region," Foreign Minister Rohitha Bogollagama told the Foreign Correspondents' Association.

"Within the region, we have to be more vigilant, more cautious," he added, saying he would raise the issue at next week's South Asian Association for Regional Cooperation (SAARC) summit. "We are looking at a regional counter-terrorism drive."

The government says neighbouring India in particular should be wary of the threat posed by the rebels' air wing -- comprised of up to five light aircraft smuggled onto the island in pieces and reassembled.

The Sri Lankan government has been trying unsuccessfully for years to convince India -- which lost around 1,000 troops in the 1990s when a peacekeeping mission turned into all-out war with the Tigers -- to become more involved in ending the conflict.

"From the point of view of brutality and lunacy, the LTTE is an easy match for the authors of the Sept. 11 hellfires," the government mouthpiece Daily News wrote in an editorial on Tuesday. "It goes without saying that those behind Sept. 11 may have taken a leaf from the LTTE."

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