Protests against police killing of black people, many initially peaceful, became eclipsed again as darkness fell by unrest across an American landscape shaken to its core by familiar eruptions along racial and law enforcement fault lines.

With cities wounded, America went into a new week with neighborhoods in shambles, urban streets on lockdown and decimated confidence about when its leaders will find the answers to control the mayhem amid unrelenting raw emotion.

There was mayhem in Washington, D.C., and multiple fires lit near the White House, where the National Guard was called in. Protesters in New York City pelted officers and set small fires and police charged into crowds to make arrests. Protesters hurled rocks and Molotov cocktails at police in Philadelphia.

Police fired tear gas and projectiles at demonstrators defying the Denver curfew. Protesters in Boston clashed with officers, throwing rocks and lighting a police vehicle on fire. Unrest spread in Chicago neighborhoods and its suburbs.

Vandalism and destruction continued in California with additional curfews declared as the state closed all downtown state buildings.

An AP tally shows about 4,100 people have been arrested over the recent days of demonstrations.

Police Tactics: Officers have doused crowds with pepper spray, struck protesters with batons, steered police cars into throngs and shoved demonstrators. Some action has been directed against people smashing windows, breaking into stores and burning cars, but many find other instances more difficult to understand. And there are questions, whether such police tactics against protesters are actually making the violence worse rather than quelling it, report Jay Reeves and Kat Stafford.

Fatal Police Shooting in Kentucky: The gunfire that killed Breonna Taylor, a black woman, and wounded one of the plainclothes police detectives who crashed through her front door has fueled a debate over so-called no-knock warrants. More than two months after police fatally shot her, the Louisville mayor has announced an indefinite suspension on the warrants that allow officers to enter a home without announcing their presence. Civil rights advocates are calling for a permanent ban, report Dylan Lovan, Michael Kunzelman and Adrian Sainz.

Behind the Protests: U.S. officials are seeking to determine whether extremist groups, either far-left or far-right, have infiltrated the protests and deliberately tipped largely peaceful demonstrations toward violence. Officials are also investigating whether foreign adversaries are behind a burgeoning disinformation campaign on social media.

Trump: The president spent time in a White House bunker during Friday night’s protests outside the executive mansion. Secret Service agents rushed him there as some of the demonstrators were throwing rocks and tugging at police barricades. Trump spent nearly an hour in the underground shelter, which was designed for use in emergencies like terror attacks.

Biden: The presumptive Democratic nominee will spend the next five months presenting himself as a calming, competent alternative to the tumultuous Trump administration. But this weekend’s unrest underscored some of the challenges he faces in conveying his message and offering the personal connections he’s known for.

The World Watches and Marches: Nations around the world have watched with deep alarm at the civil unrest in the U.S. But such eruptions no longer startle even America’s closest allies. Burning cars and American riot police have been broadcast around the globe. The story bumped news of the pandemic to second-tier status. Thousands marched in London to offer support for American demonstrators. Several thousand also marched in New Zealand’s largest city, Auckland.