Grenade wounds Thai demonstrators

Anti-government rallies have been held in Bangkok for months

A grenade blast has wounded eight anti-government protesters camped outside the Thai prime minister's office in Bangkok, emergency services say.

Demonstrators from the People's Alliance for Democracy (PAD) group have occupied the area since August.

The attack comes two days after another grenade attack on the protesters killed one person and injured more than 20.

The PAD wants the government to resign, saying it is too close to ousted former PM Thaksin Shinawatra.

The grenade exploded just after 0200 on Saturday (1900 GMT on Friday), and hit a checkpoint staffed by volunteer guards from the PAD, police said.

The protesters have been targeted by small bomb attacks in recent weeks.

Street violence

The PAD is an alliance of conservative and royalist activists.

They accuse Prime Minister Somchai Wongsawat and his recently ousted predecessor, Samak Sundaravej, of being proxies for Mr Thaksin.

The former prime minister, who is Mr Somchai's brother-in-law, was forced from office in a military coup in 2006 and remains in exile.

The PAD wants to replace Thailand's one-man, one-vote system with one in which some representatives are chosen by professions and social groups.

The protests have seen some of the worst street violence since pro-democracy activists challenged Thailand's army in 1992.