The United States has freed an Afghan convicted by an American court on charges of drug smuggling and terrorism in exchange for two U.S. citizens held in Afghanistan, authorities in Kabul said on Tuesday.

Americans Ryan Corbett and William W. McKenty III were freed, their families said. The Taliban said Khan Mohammed, an Afghan serving a life sentence in California, was released.

Two other American captives remain in Afghanistan: George Glezmann, a former airline mechanic, and Mahmood Habibi, a naturalized American who was seized soon after a U.S. strike in Afghanistan killed Ayman al-Zawahri, the leader of Al Qaeda.