As Donald Trump vowed to crack down on nationwide protests against police brutality on Monday, Republican lawmakers expressed uneasiness with the presidents rhetoric just days after a white police officer killed a Black man by kneeling on his neck.

The country is looking for healing and calm. And I think the president needs to project that in his tone. He masters that sometimes, and ... thats the tone he needs to strike right now, Senate Majority Whip John Thune (R-S.D.) told reporters on Capitol Hill when asked the presidents handling of the demonstrations.

After protests intensified in Minneapolis and other cities following George Floyds death last week, Trump predicted on Twitter that local looting could lead to shooting, a phrase with racist origins dating back to the civil rights movement in the 1960s.

Over the weekend, Trump appeared to invite his supporters to the grounds near the White House where protesters had clashed with Secret Service and U.S. Park Police, raising concerns that the unrest could escalate further.

And on a contentious call on Monday with the nations governors, Trump said they would be weak and fools if they do not dominate demonstrations in their states, some of which turned violent overnight.

If you dont dominate, youre wasting your time. Theyre going to run over you youre going to look like a bunch of jerks. You have to dominate, Trump told the nations chief executives, suggesting the military might get involved to break up protests.

Illinois Gov. J.B. Pritzker (D) challenged Trump during the call, saying he was extraordinarily concerned about his response to the protests, calling it inflammatory.

The presidents heated rhetoric over the last several days also didnt sit well with some Republican senators, who voiced concern about the message coming from the White House at an extremely volatile period in U.S. history.

It would be helpful if he would change the tone of his message, said Sen. Pat Toomey (R-Pa.) in remarks to reporters in his state.

In a speech on the Senate floor addressing the unrest over Floyds death, Sen. Susan Collins (R-Maine) urged the president to help to heal the racial divisions in this country.

Sen. James Lankford (R-Okla.) also took issue with Trumps tweet about looting and shooting, but he said the majority of the presidents public remarks about the protests and his condolences over Floyds death were positive.

I dont like the way hes done the tone on those, but I think a lot of people have picked up those [individual tweets] and just ignored everything else, Lankford said.

The Senate returned to Washington after a one-week recess on Monday evening. Lawmakers were greeted by several hundred Black Lives Matter protesters in front of the U.S. Capitol, as well as dozens of Capitol Police officers, some of whom wore riot gear.