Colin Powell was a US war hero and the first African-American US secretary of state who saw his trailblazing legacy tarnished when he made the case for war in Iraq in 2003.

The 84-year-old retired four-star general died today from complications from Covid-19.

After engineering military victory in the 1991 Gulf War, Powell was so widely popular and respected that he was considered a strong candidate to become the first ever Black US president.

He ultimately decided against running for the White House, although he later broke with his Republican Party to endorse Barack Obama.

A son of Jamaican immigrants, Powell frequently shattered glass ceilings in a pioneering career that took him from combat in Vietnam to becoming America's first Black national security advisor under then-president Ronald Reagan.

Colin Powell pictured with his family after being made US national security advisor in 1987

He was also the first African American and youngest chairman of the Joint Chiefs of Staff under Reagan's successor, George H.W. Bush.

Serving four presidents, Powell made his reputation as a man of honour distant from the political fray - an asset in the corridors of power.

George W. Bush described Powell as "an American hero, an American example, and a great American story" when he nominated the professional soldier to be secretary of state in 2000.

He made him fourth in the presidential line and, up to then, the highest-ranking Black US public official ever.

"He was highly respected at home and abroad. And, most important, Colin was a family man and a friend," the 43rd president said today.

Colin Powell addressing the UN in February 2003

Powell had a reputation for bipartisanship, straight talk and integrity, and was praised for his officer's instincts of duty and honour.

But the former US secretary of state found it Almhard to live down his infamous February 2003 speech to the United Nations Security Council about the alleged existence of weapons of mass destruction in Iraq - evidence which was later proven to be false.

"It's a blot... and will always be a part of my record. It was painful. It's painful now," Powell said in a 2005 interview with ABC News.

Born 5 April, 1937 in Harlem, New York, Colin Luther Powell's "American Journey" - the title of his autobiography - started in New York, where he grew up and earned a degree in geology.

He received a commission as a second lieutenant in the US Army, and was posted in what was then West Germany.

Powell completed two tours of duty in Vietnam - in 1962-63 as one of John F. Kennedy's thousands of military advisors, and again in 1968-69 to investigate the My Lai massacre.

Colin Powell completed two tours of duty in Vietnam

He earned a Purple Heart, but also faced questions about the tone of his report into the hundreds of deaths at My Lai, which to some seemed to dismiss any claims of wrongdoing.

Back in Washington, he quickly rose through the ranks to the pinnacle of the national security establishment, serving Reagan as national security advisor, and both George H.W. Bush and Bill Clinton as Joint Chiefs chairman from 1989 to 1993.

Powell freely admitted his liberal social views made him a strange bedfellow for many Republicans, though the party was often happy to hold him up as an example of its inclusivity.

But since 2008, he has endorsed Democrats for the presidency, twice backing Obama, and then Hillary Clinton and Joe Biden.

Colin Powell pictured with then US President Barack Obama in 2010

Powell earned a number of civilian honours, including the Presidential Medal of Freedom twice - from Bush Senior and Clinton.

He married his wife Alma in 1962. They had three children: Michael, Linda and Annemarie.