NATO Secretary-general Anders Fogh Rasmussen says: "Ambassador Gass is a highly qualified diplomat who will bring a regional perspective to this important post". 

"He knows how important the civilian and political aspects of NATO's engagement in Afghanistan are, especially as Afghans start taking the lead for their own security in the first half of this year", he added. 

Gass will officially take up his duty at a meeting of NATO foreign ministers in April to replace Sedwill, who came into office in February 2010. 

Gass' job is to ensure that the governance and development work is closely coordinated with the military campaigns. 

"We are entering a period of transition in Afghanistan which will be critical for the country's stability and security", Gass said in the NATO statement.