The militants were not handed over either to the Afghan Embassy in Islamabad or to the country's missions in Pakistani provincial capitals.
Pakistan released the group of Afghan Taliban leaders on Saturday to "further facilitate the Afghan reconciliation process". It has so far freed a total of 33 Taliban leaders.
Official sources told reporters today that the detainees were released and not handed over to authorities because they would be "bound" if this was done.
The Express Tribune reported Pakistani officials had informed families of some of the Taliban leaders freed earlier this year and in November last year about their release.
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But the families of the latest set of freed leaders have been not informed, the report quoted Taliban sources as saying.
Pakistan started the process of releasing Afghan Taliban prisoners following a request from the Afghanistan government and its High Peace Council in November last year.