Also, marine heat waves are spreading across the world. Here’s the latest at the end of Monday.

By Matthew Cullen

The mood in Los Angeles was tense this afternoon, as the city braced for a fourth day of confrontations between law enforcement and demonstrators protesting the Trump administration’s immigration crackdown. Over the weekend, the authorities responded to pockets of violence with crowd-control munitions, tear gas and flash-bang grenades.

President Trump responded by sidestepping the state’s Democratic governor and deploying 2,000 National Guard members to the city. He portrayed the demonstrations as an existential threat to the country, and called the protesters “insurrectionists,” in what may become a rationale for him to invoke the Insurrection Act.

Defense officials also said that a battalion of 500 Marines was “being mobilized” to help quell protests in Los Angeles.