"It's been a very, very serious and critical situation, " said John David, a West Virginia University Institute of Technology professor and volunteer with the South Appalachian Labor School who has been working in Fayette County.

CNN: July 7, 2012 -- Updated 0222 GMT (1022 HKT)

The new Special Representative of the Secretary-General succeeds Kai Eide of Norway, who will complete his assignment on 28 February, and to whom Mr. Ban is grateful for his intrepid spirit, strong determination and excellent leadership of UNAMA over the past two years, a critical period for Afghanistan with difficult elections and a very challenging security situation.

UN: Secretary-General