At least six policemen and a civilian have been killed and 13 wounded in a suicide attack on a governor's compound in western Afghanistan, police say.

Four attackers were killed in the assault in Farah province - one blew himself up at the gate and the others fought their way inside the compound.

They were shot dead after a gun battle lasting nearly an hour.

Government offices are frequently targeted by the Taliban. Farah is a strategic province bordering Iran.

The insurgents were armed with rocket propelled grenades, hand grenades and small arms, intelligence and police officials told the BBC.

Farah Deputy Governor Mohammad Yunos Rasuli said that the attackers wore police uniform and that he killed two of them before he was himself wounded by gunfire.

"I emboldened the police and others till the last breath. I killed two of them and rescued myself, His Excellency the governor and some 10 to 12 elders and officials. I and my son were hit by bullets. God saved us," he told Afghanistan's Channel One TV.

Mr Rasuli warned that the number of casualties may rise.

"They did not show mercy and shot everyone who came across - the office caretaker, a cleaner and others," he said.

Among the 13 injured were five civilians including two women, a one-year-old child and two elderly people, the chief doctor at Farah hospital told the BBC.

Last month two Taliban fighters smuggled themselves into the governor's compound in Kandahar, sparking a 30-minute gun battle in which both were killed.