The Liberation Tigers of Tamil Eelam, which undertook its first simultaneous air and ground assault on Sri Lankan government forces earlier this week, has said attack is the best form of defence.

"The best form of defence is offence," Tiger military spokesperson Rasiah Ilanthirayan remarked hours after the Monday clash at an air force base north of Colombo, which killed around 34 people.

Ilanthirayan, however, did not elaborate if the remarks meant the Tigers had shifted from the defensive stance they had adopted earlier, the Morning Leader Newspaper said in a front page report on Wednesday.

Meanwhile, the main opposition United National Party on Tuesday told Parliament that 18 aircraft worth more than $439 million were damaged in the predawn rebel assault on Anuradhapura airbase, "despite the government claiming otherwise".

Speaking during the debate on the Local Government and Provincial Councils (Amendment) Bill, UNP Anuradhapura District Member of Parliament P Harrison asserted he was making the disclosure to the House with "responsibility" and challenged the government to prove him wrong.

He said the Tigers have launched three air strikes against military bases and in all cases returned to their hideout in Wanni without being intercepted.