Top Democrats on Capitol Hill began to push back fervently against one of their own on Monday for suggesting that Trump administration officials should be harassed and shamed.

Senate Minority Leader Chuck Schumer (D-N.Y.) rebuked Rep. Maxine Waters (D-CA), though not by name, after the congresswoman said over the weekend that Americans should confront individuals who work for President Donald Trump and “tell them they're not welcome anymore, anywhere.”

Schumer suggested that Waters was advocating in favor of the president’s own tactics of harassing and intimidating his political opponents—at the peril of Democrats nationwide.

“We all have to remember to treat our fellow Americans, all of our fellow Americans, with the kind of civility and respect we expect will be afforded to us,” Schumer said on the Senate floor. “No one should call for the harassment of political opponents. That’s not right. That’s not American.”

He added: “The president’s tactics and behavior should never be emulated. It should be repudiated.”

Waters’ remarks come as anti-Trump resistors have been targeting top Trump officials in public, including Homeland Security Secretary Kirstjen Nielsen and policy chief Stephen Miller. Protesters have shouted down the officials, often chanting “shame!” and other phrases. Over the weekend, White House Press Secretary Sarah Sanders was kicked out of a Virginia restaurant because she works for the president.

Schumer and other top Democrats are now pushing back against those tactics more directly, arguing that they help boost Republicans.

“The best solution is to win elections,” Schumer added. “That is a far more productive way to channel the legitimate frustrations with this president's policies than harassing members of his administration.”

House Minority Leader Nancy Pelosi (D-CA) also responded directly to Waters, writing in a tweet earlier Monday: “Trump’s daily lack of civility has provoked responses that are predictable but unacceptable. As we go forward, we must conduct elections in a way that achieves unity from sea to shining sea.”

The president, for his part, escalated his long-standing feud with Waters, calling her “an extraordinarily low IQ person” and warning her about taking her anti-Trump crusade too far.

“She has just called for harm to supporters, of which there are many, of the Make America Great Again movement,” Trump wrote on Twitter. “Be careful what you wish for Max!”

Waters has long caused headaches for congressional Democratic leaders. She has been one of the leading voices calling for Trump’s impeachment, a cause that most Democrats believe is premature and would actually help vulnerable Republicans in the midterm elections.