Beau Biden, the son of Vice President Joe Biden, has died after fighting brain cancer, his family announced Saturday night.

"The entire Biden family is saddened beyond words," said the statement from the vice president. "We know that Beau's spirit will live on in all of us—especially through his brave wife, Hallie, and two remarkable children, Natalie and Hunter."

Beau Biden, 46, had a long career in public service: He was a major in the Delaware National Guard, served in the Iraq War, and was Delaware's attorney general from 2007 until earlier this year. In April 2014, he announced his intention to run for governor in Delaware, but his infrequent appearances in public in recent months had cast some doubt on those plans.

As attorney general, Beau Biden was known for prosecuting child abusers. In 2010, he abstained from running for his father's old Senate seat because at the time he was handling what he called "a case of great consequence," one involving an abusive pediatrician.

"His absolute honor made him a role model for our family," the vice president said. "Beau embodied my father's saying that a parent knows success when his child turns out better than he did."

In a statement released by the White House Saturday night, President Obama said he and first lady Michelle Obama were "grieving tonight" for their deceased friend, who "made a difference in the lives of all he touched—and he lives on in their hearts.

"But for all that Beau Biden achieved in his life, nothing made him prouder; nothing made him happier; nothing claimed a fuller focus of his love and devotion than his family," Obama said. "Just like his dad."

In a statement, Senate Minority Leader Harry Reid called Beau Biden a "wonderful, strong and courageous man," and said "it is unspeakably sad to see him leave us far too soon."

"I know Joe is very proud and he should be proud because Beau was simply a joy to know," Reid said.

Sen. Thomas Carper, who served alongside fellow Delaware Democrat Joe Biden in the upper chamber, released a brief statement on Twitter.

According to a report in Politico, the Biden family, including the vice president, was with him when he died.

Little information about Beau Biden's health had been made public in recent years. Three years after suffering a stroke, he was treated at a cancer center in August 2013 for a brain lesion. A few months later, he was said to be healthy. Last month, the Office of the Vice President told ABC News that he was being treated at Walter Reed National Military Medical Center.

Biden, along with his brother, Hunter, survived a 1972 car crash that killed his baby sister, Naomi, and his mother Neilia, Joe Biden's first wife. At the time, Joe Biden was the senator-elect from Delaware, and he was sworn in at Beau's hospital bedside weeks after the crash.

In a 2012 address to the survivors of fallen armed forces members, Joe Biden discussed the deep grief he felt after his wife and daughter died, and said he understood the "black hole you feel in your chest" after a loved one passes away.

"There will come a day, I promise you, and your parents, as well, when the thought of your son or daughter or your husband or wife brings a smile to your lips before it brings a tear to your eye," he said then. "It will happen. My prayer for you is that day will come sooner or later. But the only thing I have more experience than you in is this: I'm telling you it will come."

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