Seattle | Weeks of violent clashes between federal agents and protesters in Portland, Oregon, galvanised thousands of people to march through the streets of American cities on Saturday (Sunday AEST), injecting new life into protests that had largely waned in recent weeks.

One of the most intense protests was in Seattle, where 21 police officers were injured, including one who was admitted to hospital with a leg injury caused by an explosive, the police said. At least 45 protesters had been arrested as of early evening.