"The debriefing session of one of the scientists has concluded and he has resumed his normal duties," foreign ministry spokesman Masood Khan told AFP.

Yasin Chohan, a laboratory director at the Kahuta Research Laboratories (KRL) uranium enrichment facility, returned home Friday morning, an associate of Chohan's family told AFP.

Chohan and KRL director Farooq Muhammad were taken from their homes early December and held for questioning, according to opposition politicians and local news reports.

Some reports quoted witnesses saying Caucasian men wearing bulletproof jackets took them from their homes, triggering accusations that United States intelligence agencies were involved.

Pakistani officials denied the pair were in custody, saying they were merely undergoing "personnel dependability and debriefing programs."

WAR.WIRE