Three lorries carrying explosives have exploded inside a police compound in eastern Sri Lanka, in what is being described as an accident.
Local television showed pictures of piles of rubble, the twisted wreckage of the trucks and bodies on the ground.
Officials have revised their estimate of the number of dead and now say it is 27, not 60 as previously thought.
Dozens of people were hurt, some have been sent to Colombo for treatment.
It happened in Karayinadaru, about 50 kilometres from the eastern port of Batticaloa.
Sri Lanka endured hundreds of suicide bombings during its three-decade separatist conflict with the Tamil Tigers, but the government has had control of eastern Sri Lanka since 2007.
However, there is likely to be some suspicion that this blast was not accidental.