Earlier today, the U.S. State Department released the 2012 International Religious Freedom Report. The annual report sheds light on abuses of religious freedom worldwide and reinforces America’s commitment to make those freedoms “an integral part of our global diplomatic engagement.”
The report itself makes references to atheism (albeit in a very loose way):

Fifteen years ago, the U.S. Congress took a momentous step in support of religious freedom when it passed the International Religious Freedom Act, establishing within the Executive Branch the position of Ambassador at Large for International Religious Freedom. With this measure, the U.S. government made a bold statement on behalf of those who were oppressed, those who were persecuted, and those who were unable to live their lives at the most basic level, for the simple exercise of their faith. Whether it be a single deity, or multiple deities, or no deities at all, freedom to believe — including the freedom not to believe — is a universal human right.

http://www.patheos.com/blogs/friendlyatheist/2013/05/20/secretary-of-state-john-kerry-freedom-to-not-believe-is-a-birthright-of-every-human-being/