The U-S State Department says a man carrying a U-S passport, who was detained after allegedly trying to illegally enter Pakistan from Afghanistan, has been deported to the United States.
The U-S State Department says another man also carrying a U-S passport is being held by Pakistani authorities.
Pakistani sources have identified the men as Mohammad Tayyab and Afsar Khan.
Publicly disclosing the arrests for the first time, Pakistan Foreign Ministry spokesman Aziz Ahmed Khan told reporters Monday the two Americans were detained in Pakistan's northern tribal region more than a month ago.
Pakistani authorities have said it is not clear whether the two Americans had links to Osama bin Laden's al-Qaida terror network.
U-S and Pakistani troops are hunting for Taleban and al-Qaida fighters who may have crossed over into Pakistan and tried to blend into the local population.
Fears that U-S citizens may be among the ranks of al-Qaida have grown following the arrest in Chicago last month of U-S citizen, Jose Padilla.
Mr. Padilla is being held on charges of planning to explode a so-called dirty bomb in the U-S capable of dispersing radioactive material. He is believed to have spent time in Pakistan and Afghanistan and to have links to al-Qaida.