City and state officials had deployed thousands of National Guard soldiers, enacted strict curfews and shut down mass transit systems, but that did little to stop many cities from again erupting into unrest.

Protesters in Philadelphia hurled rocks and Molotov cocktails at police, officials said, while masked crowds broke into upscale stores in a San Francisco suburb, fleeing with bags of merchandise. In Minneapolis, a truck driver drove into a massive crowd of demonstrators nearly a week after the death of George Floyd, a black man who pleaded for air as an officer pressed a knee into his neck.

Tensions mounted outside the White House, where police fired tear gas and stun grenades into a crowd of more than 1,000 chanting protesters across the street in Lafayette Park. They scattered, piling up road signs and plastic barriers to light a raging fire in a street. Some pulled an American flag from a nearby building and threw it into the blaze. Others added tree branches. A cinder block building housing bathrooms and a maintenance office in the park was engulfed in flames.

The entire Washington, D.C., National Guard — roughly 1,700 soldiers — was being called in to help control the protests, according to two Defense Department officials who insisted on anonymity because they were not authorized to publicly discuss the matter.

As the protests grew, President Donald Trump retweeted conservative commentator Buck Sexton who called for “overwhelming force” against violent demonstrators.

At least 4,100 people have been arrested over days of protests, according to a tally compiled by The Associated Press. Arrests ranged from looting and blocking highways to breaking curfew.

In Salt Lake City, a leading anti-police brutality activist condemned the destruction of property but said broken buildings shouldn’t be mourned on the same level as black men like Floyd.

“Maybe this country will get the memo that we are sick of police murdering unarmed black men,” said Lex Scott, founder of Black Lives Matter Utah. “Maybe the next time a white police officer decides to pull the trigger, he will picture cities burning.”

Yet thousands still marched peacefully, with some also calling for an end to the fires, vandalism and theft, saying it weakened calls for justice and reform.

Minnesota Gov. Tim Walz brought in thousands of National Guard soldiers to help quell violence that had damaged or destroyed hundreds of buildings in Minneapolis over days of protests. On Sunday, in a display of force, long lines of state patrolmen and National Guard soldiers lined up in front of the Capitol, with perhaps a dozen military-style armored vehicles behind them.

Disgust over generations of racism in a country founded by slaveholders combined with a string of recent racially charged killings to stoke the anger. Adding to that was angst from months of lockdowns brought on by the coronavirus pandemic, which has disproportionately hurt communities of color, not only in terms of infections but in job losses and economic stress.

The droves of people congregating for demonstrations threatened to trigger new outbreaks, a fact overshadowed by the boiling tensions.

The scale of the coast-to-coast protests rivaled the historic demonstrations of the civil rights and Vietnam War eras.

Curfews were imposed in major cities around the U.S., including Atlanta, Chicago, Denver, Los Angeles, San Francisco and Seattle. About 5,000 National Guard soldiers and airmen were activated in 15 states and Washington, D.C.

Thousands of demonstrators marched peacefully through Boston in several protests during the day, but some clashed with officers as night fell, throwing rocks, bricks and glass bottles and torching a police vehicle.

Authorities fired volleys of tear gas to disperse hundreds of demonstrators in downtown Atlanta as a curfew took hold. Some on the fringes of a largely peaceful protest set off fireworks and burned construction materials near a park where police and National Guard troops turned out in force.

In Indianapolis, two people were reported dead in bursts of downtown violence this weekend, adding to deaths reported in Detroit and Minneapolis in recent days.