Pakistani police have detained around 50 people in connection with the deadly assault on a police training centre that left at least seven recruits and four militants dead, a senior official said on Tuesday.
Khalid Farooq, police chief of Pakistan's eastern Punjab province, told reporters at the funeral of the slain law enforcers that officials were interrogating the suspects, but gave no details.
A group of armed militants stormed the police academy on the outskirts of the provincial capital Lahore early on Monday and remained holed up in the three-storey building for eight hours until a commando operation ended the siege.
Three attackers blew themselves up to escape arrest while a fourth one was shot dead during the action.
The victims among the police were killed when militants launched the assault by throwing hand grenades on platoons in morning drills and later spraying the unarmed trainees with bullets. More than 95 people were also wounded.
Pakistan's Interior Ministry chief Rehman Malik said the attackers came from the South Waziristan tribal district, the stronghold of rebel commander Baitullah Mehsud.
He blamed Mehsud for orchestrating the attack, but did not rule out the involvement of "foreign hand".
A short, bearded man arrested while attempting to blow up a military helicopter that landed near the besieged academy was identified by authorities as an Afghan national.
Daily Times newspaper reported that the suspected militant shouted "I am Muslim" in Urdu language before security personnel overpowered him. The rest of his words were not understood by the officers.
Three other suspicious men were also taken into custody as they attempted to flee the school building with other recruits in police uniform.
The assault came less than four weeks after about a dozen assailants ambushed the Sri Lankan cricket team in the heart of Lahore, killing six law enforcers in the escort.
The recent surge in terrorist strikes in central Pakistan has sparked fears in some Western capitals about stability in the nuclear-armed country, which is struggling with economic and political crises.
International forces fighting the insurgency in Afghanistan believe the war cannot be won without rooting out militancy in Pakistan, especially its north-western regions having Al-Qaeda and Taliban sanctuaries.