Top U.S. officials are nervous about talks between the Afghan government and a man designated a terrorist by the State Department whose group has been responsible for deadly attacks against American and NATO troops.

Gulbuddin Hekmatyar, leader of the Hezb-i-Islami, has been meeting with the government of Afghan President Hamid Karzai and United Nations officials this week, pushing an agenda that includes the exit of NATO troops from Afghanistan as soon as the end of this year.