The attack took place at around 11:30 a.m. local time (0530 GMT) close to the police station at Akkaraipattu, 310 kilometers east of the capital Colombo.
Two members of the police Special Task Force and a regular policeman were among the injured and two civilians were also injured, the police added.
The attack was believed to have been launched by the Liberation Tigers of Tamil Eelam (LTTE) rebels.
The LTTE rebels have recently stepped up their attacks against the security forces in the Eastern Province.
The Norwegian-led international truce monitors intervened in the matter of security of the LTTE senior members traveling to government-held areas following an ultimatum issued by the LTTE which ended last week.
The Tigers claimed that the military should provide security to its traveling senior members and failing to do so would compel them to use their own armed forces.