A minor explosion close to an electrical transformer outside Sri Lanka's capital was reported on Monday as celebrations of the country's 60th anniversary of independence opened amid tight security.
The transformer was damaged in Mt Lavinia, 12 km south of Colombo. Police said they believe 200 grams of explosives had been used in the blast, in which no one was injured.
The incident came as the police discovered a roadside claymore mine fixed to a telephone booth overnight, also near Colombo.
Police and soldiers have been deployed in key strategic positions, and strict security procedures were being maintained in and around the capital as the main independence celebration was set to take place in the city with a military parade presided over by President Mahinda Rajapaksa.
Islandwide events also were being held to mark Sri Lanka's 1948 independence from Britain.
Security was further tightened after an explosion on Sunday at Colombo's main railway station in which a Tamil rebel female suicide bomber killed 13 people and injured more than 100.