Top US military officer General Mark Milley retires

General Mark Milley steps down on Friday after a tumultuous term as the top US military officer that saw him face repeated crises at home and abroad. 

General CQ Brown will replace him, becoming the second Black officer after Colin Powell to serve as chairman of the Joint Chiefs of Staff, at a time when the Pentagon is headed by Lloyd Austin, the country's first Black secretary of defense.

As chairman, "it was one crisis right after another," Milley told AFP last month.