Pelosi invoked Biblical scripture to reject Trump's clampdown on peaceful protesters outside the White House and she drew on past presidents - including George H.W. Bush in the aftermath of the Rodney King unrest and Barack Obama following the death of Eric Garner - as models of the nation's chief executive at a time of crisis.

"We would hope that the president of the United States would follow the lead of so many presidents before him to be a healer in chief and not a fanner of the flame," Pelosi said.

Congress appears to have shifted tone in reaction to the protesters outside its doors.

Republican Senate Majority Leader Mitch McConnell acknowledged "racism in America", and said the outrage was understandable..

McConnell said it's not only the death of Floyd at the hands of white police in Minnesota drawing protesters into the streets, but of other African Americans including Breonna Taylor in his home-state of Kentucky.

"There is no question that there is residual racism in America," McConnell told reporters. "It's been a longtime dilemma and we all wish we could get to a better place."

Several Republicans, including Senator Marco Rubio of Florida, called Floyd's death a "murder."

McConnell declined to directly comment on Trump's handling of the crisis. However, several Republicans on Tuesday suggested it would be better if Trump helped calm the nation rather than escalate the already tense conditions in Washington and across the country.

Trump was widely criticised for clearing protesters from outside the White House on Monday so he could walk across the street to hold up a Bible outside historic St. John's church. It was viewed as a photo opportunity and criticised by the congregation's bishop.

"I'm against clearing out a peaceful protest for a photo op that treats the Word of God as a political prop," said Republican Senator Ben Sasse, R-Nebraska.

"Every public servant in America should be lowering the temperature."

Senate Democratic Leader Chuck Schumer called on Defence Secretary Mark Esper and Army General Mark Milley, the chairman of the Joint Chiefs of Staff, to refuse the use of military helicopters and tear gas for "ugly stunts" .

Senate Democrats proposed, and Republicans rejected, a resolution condemning the president's actions.

Republican Senator Ted Cruz of Texas, said he was "glad the president led" by clearing the protesters from the park.

Cruz and other Republicans blamed outside agitators from the "Antifa" anti-fascist movement from intervening in otherwise peaceful protests that resulted in looting and other property damage.

Many in Congress are working on a legislative response to the eruption of anger over racial inequity.

More than 40 bills - from banning police choke holds and racial profiling to preventing the federal transfer of military equipment to local law enforcement to a long-sought federal anti-lynching law - are now under consideration on Capitol Hill.

House lawmakers could be recalled to Washington this month to vote on legislation to address police and other reforms.

Australian Associated Press