Searchlights were activated in the capital, and motorists were told to douse their lights by policemen, shortly after 9.00 pm local time, residents said.
Anti aircraft fire were heard by residents in Colombo and suburbs.
Tamil Tiger rebels had previously raided installations in the capital, but the group is now confined to a small areas in the northeast of the island.
The military has also captured a number of airfields used by the Tigers.