PORTLAND, Ore. — Federal authorities early Thursday dismantled and cleared a portion of the tent city where protesters have been blocking the Immigration and Customs Enforcement building here, arresting at least eight people who had taken part in a lengthy effort to prevent federal workers from entering their offices.

A makeshift tent city emerged here amid the turmoil surrounding President Trump’s border crackdown and family separation policies, and for the 11 days the protesters had effectively shut down ICE’s offices as they demanded the agency be abolished. The camp had swelled to more than 90 tents earlier in the week.

Federal officials had warned protesters that parts of the camp blocking entry to and exit from the building were in violation of the law, having issued notices in the days before the clearing effort. Activist Lilith Sinclair, 24, said that federal officers inside the building had been playing “mental games for days” with protesters, including blaring loud music toward the campers. She said one of those songs was Metallica’s “Enter Sandman.”

By 5:30 a.m. Thursday, officers had cleared a set of tents that had been set up across the building’s driveway, an encampment that had been full of military veterans. Stu Tanquit, one of the veterans, said earlier in the week that "the only way they will get me out is to drag me out.”

Robert Sperling, a Federal Protective Service spokesman, said authorities issued several verbal warnings via a loudspeaker, urging people to leave the premises. “Some of them did,” Sperling said. “Many did not.”

Officers will not clear the main encampment, because it is not on federal property, Sperling said, noting that his agency hopes to get ICE workers back at their desks by sometime next week.

“We’re going to maintain a presence there and ensure the safety and security of the facility,” he said.

Sperling added that the music protesters heard was not a tactic reminiscent of U.S. detainee operations, nor was it designed to push them out. “Some of the folks who were in there, they had dinner and they were playing some music,” Sperling said. "They had a barbecue, and while they were waiting, it was part of their dinner.”

The raid came hours after Trump tweeted his dissatisfaction with protesters at ICE offices in cities across the country: “Leftwing Activists are trying to block ICE officers from doing their jobs and publicly posting their home addresses – putting these selfless public servants in harm’s way,” he wrote. “These radical protesters want ANARCHY – but the only response they will find from our government is LAW AND ORDER!”

By 7:30 a.m., lines of Department of Homeland Security and ICE officers in tactical gear surrounded the building, in Portland’s South Waterfront neighborhood. Some ICE officers wore black scarves over their faces. “They were threatening our family members,” one officer said, declining to elaborate.

Portland Mayor Ted Wheeler tweeted last week that he would not instruct Portland police to aid federal officers in clearing away protesters, but Thursday morning some officers were nearby blocking the major thoroughfare near the ICE offices and diverting traffic.

Protesters said they plan to stay in what remains of the tent city, and Thursday some were holding signs, blowing bubbles or playing music – Eazy-E and Wipers – aimed toward the federal officers. Danialle James, 32, was still in her pajamas as she yelled toward the line of officers in riot gear. “I’m here for the long haul,” she said.

Since the Portland Occupy ICE encampment popped up here, tent cities like it have arisen near ICE buildings in larger cities, such as New York and Los Angeles. Protesters here said they were aware that the way they respond to raids will be watched by those other camps.

“We’re calling out the state of Oregon for allowing ICE … to operate within our borders,” Sinclair said. “We’re participating in passive resistance.”

The message, she said, hasn’t changed because of the early-morning effort to disrupt the protest: “It’s not a radical idea to say we should not be putting people in concentration camps in 2018.”