The freed soldiers were handed over to members of a jirga or tribal council in Ladha, a village in South Waziristan where they had been abducted by militants on Aug. 30, a local intelligence official said on condition of anonymity because of the sensitive nature of his job.
Army spokesman Maj. Waheed Arshad had no confirmation of the troops' release.
The freed soldiers were to be handed later Monday to government officials in Wana, the main town in South Waziristan, a rugged region where al-Qaida- and Taliban-linked militants operate, the intelligence official said.
It was not clear whether there were any conditions to the soldiers' release. Militants had earlier demanded that authorities withdraw the military from the area and free more than a dozen of their comrades.
Six of the abducted troops were released last week in what an official said was a "goodwill" gesture to the jirga negotiating their release.
In the Nawaz Kot area of South Waziristan, meanwhile, militants opened fire from their car at the security post, drawing retaliatory fire from troops based there, Arshad said. The militant leader, Qari Sana, and four fighters were killed in the clash, while three others were wounded but managed to flee, Arshad said.
Pakistan - a close U.S. ally in the war against terrorism - has deployed some 90,000 troops to the region bordering Afghanistan to track down militants.
Militants have stepped up attacks in recent weeks against the military in the tribal border areas, adding to the government's woes at a time of gathering political crisis in the country.
The United States has been pressing Pakistan to do more to crackdown on militants in the region amid its concern that al-Qaida may be regrouping in there.