The White House, Office of the Press Secretary. May 1, 2012.
In May 2010, in Washington, DC, President Obama and President Karzai committed the United States and Afghanistan to negotiate and conclude a strategic partnership that would provide a framework for our future relationship. On May 1, 2012, President Obama and President Karzai signed the Enduring Strategic Partnership Agreement between the Islamic Republic of Afghanistan and the United States of America.
http://www.whitehouse.gov/sites/default/files/2012.06.01u.s.-afghanistanspasignedtext.pdf [PDF format, 9 pages].