Former US vice-president Joe Biden has claimed he could have beaten Donald Trump if he had run in the 2016 presidential election. The Democrat, who served under Barack Obama, voiced regret about not running but said that his son's cancer and subsequent death were too much to handle.

"I had planned on running for president and although it would have been a very difficult primary, I think I could have won," he told an audience at Colgate University in Hamilton, New York.

"I don't know, maybe not. But I thought I could have won."

According to The Hill, Biden continued: "I had a lot of data and I was fairly confident that if I were the Democratic Party's nominee, I had a better than even chance of being president."

The death of his son Beau from brain cancer, however, weighed on his decision to join the primary race against Hillary Clinton and Bernie Sanders for the Democratic nomination.

"I lost part of my soul," he said as he cleared his throat, according to the Washington Post.

"The press began to think I was playing a game, but I couldn't tell them about my boy," he said. "He wanted me to run. My son Hunter, my daughter Ashley, my wife, all thought I should."

He added: "I didn't. At the end of the day, I just couldn't do it."

Rumours about his decision to challenge Clinton and Sanders circulated after Beau Biden's death in May 2015. He officially dismissed those rumours that autumn during an announcement in the White House Rose Garden.

Biden told the students at Colgate that he could not promise his complete dedication to a campaign.

"No man or woman should announce for president of the United States unless they can look the public in the eye and say, 'I promise you I am giving 100% of my attention and dedication to this effort,'" he said.

"Do I regret not being president?" he said. "Yes. Do I regret not running for president, in light of everything that was going on in my life at the time? No."

According to the Post, Biden then took aim at the man who did become president. He said Trump's attempts to delegitimise the press as fake news was "the first act of any political scoundrel".

"We should all have hope that not knowing anything about the job before he did it he can grow more into the job and understand that the United States is the essential nation in the world in the year 2017," he said.