Police said attackers have gunned a local employee of the US embassy in Islamabad, though the motive that triggered the strike is still unclear.
Police identified the dead employee as Iqbal Baig, saying he worked for the US Drug Enforcement Agency. They say Baig was killed early Sunday morning at his home.
The US embassy did not immediately respond to a request for comment. Pakistani police officer Khalid Awan, who confirmed Baig's slaying, said US embassy security officials had visited the crime scene.
Baig belonged to a minority Muslim Shia sect known as the Ismaili. Ismailis largely live in peace in Sunni-dominated Pakistan, though Islamic extremists in the country view Shiites as heretics. Gunmen in May shot and killed 50 Ismailis in the southern port city of Karachi.