At least 12 people including four policemen were killed and seven others wounded in the brazen assault late Monday staged by militants disguised in police uniforms, they said."A total of 243 prisoners have escaped, six of them were later arrested by police," DI Khan Commissioner Mushtaq Jadoon told, adding that "30 among the escaped prisoners were hardcore militants".A security official said the jail held up to 5,000 prisoners including some 300 militants involved in attacks on security forces and sectarian killings.Jadoon said the fighters had planted dozens of explosive devices in the jail and 14 of them had so far been defused."Police and other law enforcing agencies are busy in clearing the jail," he said, adding authorities have imposed a curfew in the city and asked residents to stay at home."Through media, we appeal to the people to stay at home. It is to avoid any damage if army, police and paramilitary take any action," he added.Jadoon said around 50 to 60 militants managed to enter the jail as others fired rockets from outside."First they destroyed a police armoured vehicle parked at the front gate," he said, adding that two policemen were killed in the initial rocket attack.The Taliban claimed responsibility for the jail attack."Some 150 Taliban, including 60 suicide bombers, attacked the Central Prison and managed to free about 300 prisoners," Taliban spokesman Shahidullah Shahid told AFP by telephone.K-P prisons chief Khalid Abbas said the gunfight raged for three hours, with militants wearing police uniforms entering the facility after bombing its outer wall and throwing hand grenades at prison guards.After the battle abated, security forces searched the prison which was plunged into darkness with an electricity outage, and counted inmates by flashlight to determine how many had escaped, he said.Residents in Dera Ismail Khan reported hearing loud blasts and gunfire, and said the electricity supply to several parts of the city had also been suspended.A local police official said he saw militants carrying rocket launchers and firing at the jail."Militants were firing rockets at the jail and I also heard gunfire from inside the building," the official said, speaking on condition of anonymity.Spokesperson for the K-P government Shaukat Yousafzai confirmed the army had been called in to quell the militant attack.Last year, nearly 400 prisoners were freed when the Taliban attacked a prison in Bannu.