Lahore, July 30: Pakistani Taliban militants, some of them disguised in police uniforms, attacked a prison in northwestern Pakistan with machine guns and grenades Monday, freeing more than 240 prisoners, including 25 jailed terrorists.

Officials say 12 people, including four policemen, were killed in the attack that lasted for at least three hours.   Seven policemen were wounded in the assault on the prison in the town of Dera Ismail Khan, a city in Khyber Pakhtunkhwa province, close to the lawless tribal regions bordering Afghanistan where Taliban and al-Qaida-linked insurgents are active.

Authorities say at least six prisoners who escaped have been captured.  Army soldiers were called in as reinforcements.

Authorities have imposed a curfew on Dera Ismail Khan. Police and soldiers have sealed off the area.

A Pakistani Taliban spokesman has claimed responsibility for the attack, saying about 150 militants were involved, including several suicide bombers. The spokesman declared the attack a success.

Residents living near the prison say they heard several large explosions before the attackers opened fire with machine guns and rocket-propelled grenades.

About 5,000 inmates live in the prison, including as many as 250 convicted terrorists. About 40 are so-called "high-profile" prisoners.