The No. 2 US diplomat will travel to Vienna this week to take part in talks over Iran's nuclear program, the State Department said on Sunday.
In a statement, the State Department said Deputy Secretary of State Bill Burns would be among the US officials taking part in the latest round of nuclear talks, which include six world powers and Iran and are scheduled for Monday to Friday.
The participation of Burns, who led secret US-Iranian negotiations that helped bring about a Nov. 24 interim nuclear agreement between Iran and the major powers, could signal that the United States is intensifying efforts to break a logjam in the nuclear talks.