Speaking at a virtual fundraiser that Duckworth also attended, Biden said that the comments were "disgusting, sickening" and demonstrated the "depravity of what’s going on in the White House right now."
"While in fact (Trump is) coddling Putin — Putin carries him around like a puppy in one of those little puppy cages. While that's going on he attacks, he attacks the senator from Illinois who is a literal hero, combat veteran, lost both legs fighting for her country, and he says she’s not a patriot. Folks we cannot let this stand," Biden said.
The attacks against Duckworth began on Sunday after the Democratic lawmaker from Illinois was asked in an interview on CNN whether statues of George Washington should be removed because he owned slaves. Duckworth said she thought there should be a "national dialogue" on the issue.
Duckworth's response drew criticism from Fox News host Tucker Carlson, who went on his show and called her "a deeply silly and unimpressive person" and said that Duckworth and other Democratic leaders "actually hate America."
"Can you really lead a country that you hate?" Carlson continued, noting that Duckworth was being considered as a possible Biden running mate.
Trump shared a video on Twitter of Carlson's segment attacking Duckworth and his campaign issued a statement saying that "Duckworth is now using her military service to deflect from her support for the left-wing campaign to villainize America's founding."
Duckworth shot back at Carlson after his segment aired, tweeting "Does @TuckerCarlson want to walk a mile in my legs and then tell me whether or not I love America?"
Duckworth lost both of her legs during the Iraq War in 2004 when a rocket-propelled grenade hit the helicopter she was co-piloting.
During the virtual fundraiser Tuesday evening, Duckworth also spoke to attendees, criticizing Trump.
"Instead of trying to bring our country back together, he spent his time defending dead Confederates who took up arms against this nation and engaging in xenophobic and racist language geared towards many Americans, including the Asian American and Pacific Islander community," Duckworth said.