Colombo: At least seven prisoners were injured when a powerful grenade exploded inside a prison in Sri Lanka's eastern Batticaloa district Friday morning, police said here.

Police spokesman, Senior Superintendent of Police Ranjith Gunasekara, said the grenade explosion took place in room number 10 of the Batticaloa prison Friday morning, injuring seven inmates, including four members of the Eelam People's Democratic Party (EPDP), a former militant group.

"Police and prison authorities are carrying out a major search operation in the Batticaloa prison," Gunasekara said.

EPDP officials in Colombo accused a rival Tamil party, which was also involved in terrorism earlier, for the attack and said their cadres were seriously wounded in the attack.

The EPDP, led by minister Douglas Devananda, is a coalition partner of the ruling United People's Freedom Alliance (UPFA) of President Mahinda Rajapaksa.

Source : IANS