Former Vice President Joe Biden lost his cool with a reporter who asked about a potential conflict of interest between his role in charge of U.S. policy toward Ukraine and his son Hunter’s position at a Ukrainian gas company.

The 2020 Democratic presidential candidate was speaking Friday in Los Angeles, Calif. at the SEIU Unions for All Summit.

“How was your role as Vice President in charge of policy in Ukraine and your son’s job in Ukraine, how was that not a conflict of interest?” the reporter asked.

WATCH:

WATCH: Joe Biden explodes when a reporter asks a very simple question: “How was your role as Vice President in charge of policy in Ukraine and your son’s job in Ukraine, how is that not a conflict of interest?” Biden: “I’m not going to respond to that!” What is he hiding? pic.twitter.com/jbycKLARhE — Trump War Room (@TrumpWarRoom) October 4, 2019

“It’s not a conflict of interest,” a visibly frustrated Biden responded. “There’s been no indication of any conflict of interest, from Ukraine or anywhere else. Period. I’m not going to respond to that! Let’s focus on the problem. Focus on this man, what he’s doing, that no president has ever done. No president!”

Hunter Biden’s lucrative role on the board of Ukrainian natural gas company Burisma Holdings along with the fact that his father, as vice president, pressed for the firing of the country’s top prosecutor, who was looking into the company, has led many to allege a conflict of interest. (RELATED: Nikki Haley Scolds Kamala Harris For ‘Embarrassing’ Defense Of Joe Biden)

President Donald Trump in his infamous July 25 call asked Ukrainian President Volodymy Zelensky to look into the matter along with potential interference in the 2016 U.S. elections.