Tamil Tigers had previously raided petroleum installations in the capital Colombo using low flying light aircraft. The group has published pictures of modified Zlin Z-143 aircraft claimed to have been used in the raids.
They are employing a 'Bed check Charlie' strategy successfully used in Korea by communist forces against the United States.
Some of the 'Charlies' were as old as Polikarpov bi-planes dating from before World War II. The slow moving aircraft slipped under American radar, dropped a few bombs and flew away, leaving faster North American F-86 Sabre jets helpless.
Similar tactics have also been used in other wars, including during World War II and separatist conflicts.
Sri Lanka's air force has claimed one kill of guerrilla aircraft so far.
The attack on the Kelanitissa power station in north Colombo had damaged one steam power plant and set fire to an oil cooling unit of another pow