The confrontation between protesters and federal paramilitaries in Portland escalated early on Sunday morning, when demonstrators finally broke down a steel fence around the courthouse after days of trying. The federal agents fired waves of teargas and “non-lethal projectiles” to drive back thousands besieging the courthouse to demand Donald Trump withdraw the paramilitaries, ostensibly sent to curb two months of Black Lives Matters protests. The city police, who had largely withdrawn in recent days, declared a riot and joined federal agents in making arrests. Portland is now the focal point of nationwide protests sparked by the killing of George Floyd in Minneapolis in May. But many other cities are affected. In Seattle, in neighbouring Washington state, authorities said rocks, bottles and fireworks were thrown at officers who used flash bangs and pepper spray. The police chief, Carmen Best, told reporters she had not seen federal agents the Trump administration sent to the city. In Oakland, California, after a peaceful protest, a courthouse was set on fire. In Aurora, Colorado, a car drove into a Black Lives Matter protest and a demonstrator was shot. In Richmond, Virginia, a dump truck was set on fire and police appeared to use teargas to disperse protesters. In Portland, authorities erected the steel barrier around the federal courthouse after two earlier fences were swiftly torn down. The latest barrier was held in place by large concrete blocks and proved impregnable for several days. Early on Sunday, protesters attempted to bring it down with teams pulling on ropes, but the ropes broke. Then they used a chain, a section of the fence gave way, and the rest was toppled to huge cheers before the crowd was driven back by teargas and rubber bullets. “Fuck the feds,” shouted a young woman in a helmet and gas mask who declined to give her name. “You want war? We’ll give you war. We will win.” More than 5,000 people, one of the largest crowds to date, turned out for the protest on the two-month anniversary of Floyd’s death at the hands of a police officer. But support for the latest Portland protests has also been driven by the president deploying federal agents to the city dressed in camouflage and using unmarked white vans to snatch protesters off the streets, a tactic the mayors of several major cities called “chilling” in a letter to the Trump administration. “These are tactics we expect from an authoritarian regime – not our democracy,” the letter said. Saturday night’s protest began peacefully as two groups formed to stand as “protection” for the demonstrators, the Wall of Moms and the Wall of Veterans, lined up in front of the fence. A protester held a sign reminding the president: “You said you wanted a wall”. Amid chants of “Black Lives Matter” and “Feds go home”, some protesters shot fireworks over the fence. Officers, drawn from the border patrol and US Marshals Service among other agencies, responded with teargas. As the days have ticked by, each side has become more experienced in dealing with the other. Last week, protesters began bringing leaf blowers to drive back the teargas. Federal agents started using them too, setting off a strange, noisy duel and small tornadoes of whirling gas. Gas masks have sold out in Portland and beyond. One group is running a production line of homemade shields, constructed from cut-up plastic barrels. A man arrived dressed in a knight’s suit of armour, which proved good protection against some of the projectiles the federal agents fire but was less convenient when it came to sprinting away from teargas. Other demonstrators are copying the tactics of Hong Kong protesters and using umbrellas as shields. But they provided little protection once federal agents started firing rubber bullets and other projectiles, wounding several people. As the crowd pulled back, some protesters marched on the nearby Marriott hotel after word spread that federal agents were staying there. The demonstrations are confined to a few, largely boarded up blocks of downtown Portland, around the federal courthouse, county jail and city police headquarters. But their impact has grown as Trump’s deployment of federal agents has increasingly come to be viewed as a political ploy to provoke conflict. The president has vowed to send a “surge” of federal forces to other Democratic-run cities, ostensibly to quell crime. The mayors of 14 cities, including Chicago and Los Angeles, published a letter accusing the president of an abuse of power and alleging that “federal law enforcement is being deployed for political purposes”, amid suspicions that Trump is attempting to paint himself as a law and order president in the run up to the election. On Saturday the assistant US attorney for Oregon, Craig Gabriel, told reporters he supported the right to participate in “large and even rowdy protests” but condemned assaults against federal officers with “bricks, metal ball bearings, commercial grade fireworks”. He said several agents had sustained burns and other wounds. Gabriel said the US attorney’s office is “committed to de-escalating tensions” using the now toppled fence. “The fence is the primary way that officers are seeking to de-escalate tension,” he said. “Before the fence was up, we had some violent agitators come up to the courthouse steps, come up to the front door, rip off the plywood and shatter the glass door. “The fence was put up just to create some space. The fence was put up so that the peaceful protesters could focus on Black Lives Matter and racial justice.” Now the fence is down. It’s not clear if the federal authorities will attempt to put it back up or try to build a stronger barrier. But its fall is only likely to encourage the protesters to keep up the pressure.