A bomb blast hit house of a former Thai prime minister late Sunday night, leaving at least 11 injured, police said Monday.

Unidentified gunmen threw an M-67 grenade in front of Bangkok residence of Banharn Silpa-Archa, who are now Chat Thai Party Chief advisory, injuring three policemen and eight people, one of them in critical condition, Bang Yikhan police said.

The explosion occured around 10:20 p.m. when two men on a motorcycle threw the grenade at the house, the Bangkok Post website quoted Pol Lt Col Wirote Thongpraphai as saying.

The grenade hit the house's wall and fell onto the street and then exploded, three policemen on duty providing security for the Banharn and his family members were slight wounded.

Seven people waiting for buses at the bus stop nearby were injured and a woman on a passing by car was seriously wounded.

All the injured was admitted to hospitals.

Banharn's house was attacked by a grenade on March 29, leaving one injured.