Beau Biden, the son of US Vice President Joe Biden, has died after battling brain cancer, his family have announced.
"In the words of the Biden family: Beau Biden was, quite simply, the finest man any of us have ever known," Joe Biden said in a statement.
Earlier this month, 46-year-old Beau was reported to be undergoing treatment at Walter Reed Army Medical Center outside Washington.
Beau had "worked to establish the rule of law" in war-torn Kosovo as a young lawyer.
He went on to become a major in the Delaware National Guard, fought in the Iraq War and was awarded the Bronze Star.
Beau later became Delaware's Attorney General, "He fought for the powerless and made it his mission to protect children from abuse," his father said.
"More than his professional accomplishments, Beau measured himself as a husband, father, son and brother.," the statement reads
"His absolute honour made him a role model for our own family. Beau embodied my father's saying that a parent knows success when his child turns out better than he did," Joe Biden added.
"Michelle and I are grieving tonight," President Barack Obama said in a statement.
"Like his dad, Beau was a good, big-hearted, devoutly Catholic and deeply faithful man, who made a difference in the lives of all he touched - and he lives on in their hearts."