Colin Powell’s family says the former top U.S. general and secretary of state had a form of blood cancer that left him vulnerable to infection, before his death from COVID-19 complications on Monday at the age of 84. Although Powell was fully vaccinated against COVID-19, he was struggling with both Parkinson’s disease and multiple myeloma, which left him severely immunocompromised.

On Monday, President Biden ordered flags at the White House to be flown at half-staff in Powell’s honor until Friday, and top administration officials were effusive in their praise of Powell. This is Secretary of State Tony Blinken, Defense Secretary Lloyd Austin and Vice President Kamala Harris.

Secretary of State Antony Blinken: “Today a grateful nation observes the end of a distinguished career and celebrates 35 years of service and victory.”

Defense Secretary Lloyd Austin: “The world lost one of the greatest leaders that we have ever witnessed.”

Vice President Kamala Harris: “You know, what an incredible American.”

As chair of the Joint Chiefs of Staff, Powell was the architect of the U.S. invasion of Panama in 1989 and oversaw the U.S.-led war on Iraq in 1991. As secretary of state under George W. Bush, Powell gave false testimony to the U.N. Security Council in 2003 about nonexistent weapons of mass destruction in Iraq, paving the way for the U.S. invasion and occupation. By many estimates, the war killed over 1 million Iraqis.