Former Vice President Joe BidenJoe BidenBiden: 'I don't need an Obama endorsement' Bill Press: How will history judge us on impeachment? Hillicon Valley: Trump officials propose retaliatory tariffs over French digital tax | FBI classifies FaceApp as threat | Twitter revamps policies to comply with privacy laws | Zuckerberg defends political ads policy MORE on Monday tore into fellow Democratic presidential candidate Pete ButtigiegPeter (Pete) Paul ButtigiegBiden: 'I don't need an Obama endorsement' Poll: Biden leads Warren by 6 points in Illinois Saagar Enjeti: What conservatives could learn from Bernie Sanders MORE over his health care proposal, saying the South Bend, Ind., mayor “stole it.”

“He stole it,” Biden told reporters while on his campaign bus in Iowa, adding that he would have been criticized had he copied another rival’s plan.

“What would you have done to me? You’d have torn my ears off,” he said, according to Reuters.

A Buttigieg campaign aide noted that the candidate had been proposing “Medicare for All who want it” since before Biden announced in April that he was running for president.

Buttigieg unveiled his proposed health care plan in September, according to his campaign website.

Biden’s comments come as both men look to gain support in Iowa less than three months before Democrats in the state hold their nominating contest.

Recent polls have shown Buttigieg surging ahead in both Iowa and New Hampshire, while Biden remains at the top of national polls of Democratic voters.

Biden has advocated for expanding the Affordable Care Act, the signature health care law born under the Obama administration in which Biden served as vice president. He’s proposed adding a “public option” that would allow individuals to select a government plan while others continue using private insurance. 

Buttigieg, like Biden, has diverged from progressive Sens. Elizabeth WarrenElizabeth Ann WarrenBiden: 'I don't need an Obama endorsement' Poll: Biden leads Warren by 6 points in Illinois Trump campaign steps up attacks on Biden MORE (D-Mass.) and Bernie SandersBernie SandersSanders meets with MLB Commissioner Rob Manfred Poll: Biden leads Warren by 6 points in Illinois Saagar Enjeti: What conservatives could learn from Bernie Sanders MORE (I-Vt.), who are backing "Medicare for All" proposals that would do away with private insurance.

Their proposals would not allow people to keep their private insurance. Warren this fall shifted her stance slightly, saying she would work to expand insurance immediately if she is elected president, with the goal of moving to Medicare for All by her third year in office.