Reinforced with gunships and heavy weaponry, some 500 of the forces had been stationed near Afghanistan's border with Pakistan's North Waziristan region, a senior Pakistani government official told our correspondent on condition of anonymity on Sunday.
The official went on to explain that the motive behind the move was yet unknown, but that the deployment could be part of a military drill to later launch a ground assault against the Taliban-allied Haqqani network of militants.
Tribal sources, meanwhile, said that a curfew had come into force, preventing the Pakistani troops' freedom of movement in the violence-hit region.
Last month, former US Joint Chief of Staff Admiral Mike Mullen claimed that Pakistan's intelligence agency was supporting the network, which has been blamed for assault on the US embassy in the Afghan capital, Kabul. "The Haqqani network, for one, acts as a veritable arm of Pakistan's Inter-Services Intelligence agency," he had asserted.