The eight-member gang led by former fighters of the banned Jaish-e-Mohammad militant group was based in Quetta, the capital of southwestern Baluchistan province, a senior police official said.
They used to collect materials and volunteers from the central province of Punjab, the official said, requesting anonymity.
The suspects were arrested in Punjab over the past few days.
The police are crowing.
"During the interrogation they confessed to having carried out a series of suicide bombings and bomb blasts against foreign forces in Afghanistan over the past several years,'' he said.
He identified the gang leaders as Mufti Saghir Ahmed, a veteran of the 1980s war against invading Soviet troops in Afghanistan, and wanted militant Mohammad Safeer.
Both are members of the Jaish group, he said.
Safeer was wanted over an attack on a church in the Pakistani town of Taxila in 2003.
"The suspects were preparing remote-controlled devices for the Taliban in Afghanistan,'' the official said.
"It's a major breakthrough in the fight against terrorism and reflects Pakistan's strong commitment to fight militancy,'' a senior security official said.
But the question remains: if these suspects were known, wanted men, why weren't they stopped last year, or the year before, or the year before that? Who else is doing the same thing in Pakistan and yet won't be stopped this year, or next year, or the year after? I still get the feeling that Pakistan is trying to placate both sides, rather than treating Islamic fundamentalism as an existential threat.