The Tamil Tigers have said that their airforce has attacked oil refining facilities and storage tanks in Colombo, the Sri Lankan capital.
The Sri Lankan government has not said if any of the targets were hit but the rebel announcement came just hours after government anti-aircraft guns opened fire around the capital late on Saturday night.
The apparent air-raid came as Sri Lankans watched their cricket team play Australia in the final of the world cup.
"The Tamileelam air force bombed two facilities that supply fuel to the Sri Lankan military, especially their air force," Rasiah Ilanthirayan, a rebel spokesman said by telephone from the Tiger stronghold of Kilinochchi in the north of the country.
"The two squadrons returned safely after the mission and the pilots have confirmed that they have hit the targets."
The rebels who are fighting for a separate Tamil homeland in the Indian Ocean island nation which they refer to as Tamileelam.
Capital blacked out
The Sri Lankan military did not officially confirm the incident but said that Colombo's air defence system was activated and anti-aircraft guns were fired.
In addition, the country's only international airport, an adjoining air force base and the entire capital were blacked out after the military detected unknown aircraft approaching Colombo.
"We are doing some air missions, we are investigating ," Ajantha Silva, an air force spokesman, said.
The Tamil Tiger air force, which consists of two converted civilian aircraft, carried out their first ever air-raid in March when they attacked an airforce facilty north of Colombo.