Sri Lanka's military says Tamil Tiger rebels have bombed an air force base next to the country's international airport, killing two airmen and wounding 17 others.

Air force spokesman Ajantha Silva says Tamil aircraft dropped explosives early Monday on the air base, north of the capital, Colombo.

Rebel spokesman Rasiah Ilanthiraiyan confirmed the Tamil Tigers used their aircraft for the first time in a combat mission. He threatened that more attacks may follow, saying steps must be taken to prevent Sri Lanka's air force from bombing Tamil civilians.

Government sources say the attack did not damage the adjacent civilian airport, which has been closed as a precautionary measure.

At least four thousand people have been killed in a new wave of fighting since 2005 between government troops and rebels battling for an independent homeland for Sri Lanka's ethnic Tamil minority.

The fighting has occurred despite a truce that has been in place since 2002.