Former US Secretary of state Colin Powell, who had served in the first Republican administration of President George W. Bush, Sunday announced he was backing Democratic presidential candidate Barack Obama in next month's election.
Making the announcement in the weekly "Meet the Press" on NBC, Powell cited Obama's "ability to inspire" and the "inclusive nature of his campaign".
Powell described Obama, 46, as a person with "both style and substance. I think he is a transformational figure."
The announcement by Powell, a retired general and a Republican, comes as a further blow to Republican candidate John McCain, who continues to lag well behind Obama in opinion polls less than three weeks before the Nov 4 election.
From 2001 to 2005 Powell had served as Secretary of State in Bush's first administration, the first African-American to hold the top US diplomatic post.