Pakistan on Thursday said it had taken into custody 12 Taliban members in connection with a school massacre that killed 153 people in December, the country's worst ever terror attack.
Among those detained was the imam of a government-run mosque in the northwestern city of Peshawar where the attack took place, according to a Pakistan Army spokesman.
Six of the suspects were arrested in Afghanistan while another six were arrested in Pakistan. All 12 were in Pakistani custody on Thursday.
"Six terrorists of this group were arrested in Afghanistan," army spokesman Major General Asim Bajwa told a press conference in Islamabad.
"Afghanistan arrested these terrorists after Pakistan's army chief provided them with leads during his visit soon after the attack," he said.
Pakistan believes that 27 conspirators were involved in the attack in total, Bajwa said.
"The intelligence agencies of both countries worked together and we are very thankful to Afghanistan," he continued, adding that nine Taliban militants had been killed during the Afghan raid while the rest remain at large.
One of those detained, Maulvi Abdus Salam, was the "imam of a mosque whose salary was paid by the government, even then he became part of this gang knowingly," Bajwa said.
Bajwa said two suspects had confessed and those arrested could face trial by military courts formed in the aftermath of the Peshawar attack.
Pakistan has stepped up its efforts against militancy in the wake of the attack.
The government has also reinstated the death penalty in the cases of people convicted of terrorism, with 22 people executed so far.
Pakistan last year began a long-awaited offensive against the Taliban in the restive tribal areas following the break down of peace talks.
Bajwa said that almost 1,700 militants had been killed as a result of an offensive in North Waziristan district and that civilians displaced by the fighting would be allowed to return by March.
The casualty count is impossible to verify because journalists are not allowed into the area.
Critics claim there have been many civilian casualties as a result of air strikes and shelling, but according to the army, no civilians have died.