Joe Biden hints at 2020 run: Save your energy, 'I may need it in a few weeks'

Members of the International Association of Fire Fighters cheer as former U.S. Vice president Joe Biden speaks at the group's legislative conference March 12, 2019 in Washington, DC. (Photo by Win McNamee/Getty Images)

Former Vice President Joe Biden is criticizing President Donald Trump's leadership and questioning Republicans' commitment to middle class America, teasing out themes of a possible 2020 presidential run.

Biden, a Democrat, spoke Tuesday to a gathering of the International Fire Fighters Association.

He has not announced a presidential bid, but the audience waved "Run Joe, Run" signs. Biden asked them to save their energy a little longer, because "I may need it in a few weeks."

Biden repeatedly ripped into Republicans, questioning those who oppose collective bargaining rights, saying: "Who the hell are these guys?"

He also criticized the Republican-championed tax cut signed into law by Trump, arguing they benefit the wealthy at the expense of the middle class.

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