Africa Day, celebrated annually on May 25th, marks the birthday in 1963 of the Organization of African Unity, precursor to the present-day African Union.
In a statement, the U.S. State Department said Washington enjoys a "dynamic partnership" with African countries and regional organizations.
It said the United States is committed to work closely with the African Union, which the statement called a force for positive change in Africa.
In his Africa Day message, UN Secretary General Kofi Annan called for decisive and bold international action in response to what he called the special needs of Africa.
Some information for this report provided by State Department, UN info service and dfid.gov.uk