Suspected separatist Tamil rebels detonated a roadside bomb in eastern Sri Lanka on Wednesday, killing six policemen and one civilian, the military said, as soldiers found 12 similar bombs hidden elsewhere.
The rebels set off the bomb as a bus carrying the policemen drove past a university in Batticaloa district, military spokesman Brig Prasad Samarasinghe said.
Six police officers aboard the bus died in the blast, and a passer-by was also killed, he said. "These officers were going on leave," he added.
There was no immediate comment from the rebels, but roadside bombs, which can be detonated by remote control, have been the favoured weapons of the rebels in their fight for a Tamil homeland in Sri Lanka's northeast.
Separately on Wednesday, a search team comprising found 12 similar bombs buried in abandoned land near Vavuniya in northern Sri Lanka, local police chief MA Gnanaratne said.
Vavuniya is the last government-held garrison town before rebel-held areas start in the north.
Police arrested two suspects who are being questioned, said Gnanaratne without giving further details.
The rebels have been fighting since 1983 to establish the homeland, following decades of discrimination by the Sinhalese-dominated government.
More than 65,000 people died in the conflict before the ceasefire brokered by Norway.
This 2002 truce is still officially in effect, but has virtually collapsed since the resurgence of large-scale fighting last year that left more than 3,600 people dead.