A Pakistani army spokesman says 12 local Taliban militants involved in a deadly school attack late last year have been arrested.

Maj. Gen. Asim Saleem Bajwa told a media briefing Thursday that another nine members of what is believed to be a 27-member cell have already been killed.

Bajwa credited the cooperation by neighboring Afghanistan — where six of the men were arrested based on tips from Pakistani intelligence.

The Dec. 16 attack on an army-run school in the city of Peshawar is one of the country's worst-ever terrorist incidents.

The Taliban are a loose umbrella of dozens of local militant groups bent on toppling the Pakistani government and installing their own harsh brand of Islamic governance. Taliban attacks have killed tens of thousands of Pakistanis in the past decade.