Interstate 5 in Eugene.

A group of demonstrators waving Palestinian flags blocked travel lanes on Interstate 5 Monday morning in Eugene, stopping all southbound traffic for 45 minutes.

The demonstration began around 10 a.m. near the Barlow Bridge, the Oregon State Police said in a press release. State troopers arrested “dozens” of people on allegations of disorderly conduct, state police officials said, but they did not release the names of the people in custody or additional details about their arrests.

At least one of the protesters was found with a gun, they said. 

The southbound lanes of I-5 are now open.

“Oregon State Police supports an individual’s right to lawfully protest and express concerns over world events,” an unnamed spokesperson for the agency wrote in the press release. “However, today’s actions put Oregon’s motorists in danger as well as the protestors who blocked the roadway.”

Monday’s protest came on the day of a planned “coordinated economic blockade to free Palestine,” according to a website from advocates of the action.

Pro-Palestinian also demonstrators blocked roadways in Illinois, California and New York, temporarily shutting down travel into Chicago O’Hare International Airport and onto the Golden Gate and Brooklyn bridges.

In Chicago, protesters linked arms and blocked lanes of Interstate 190 leading into one of the nation’s busiest airports around 7 a.m.

Traffic in the San Francisco Bay Area was snarled for hours as demonstrators shut down all vehicle, pedestrian and bike traffic on the Golden Gate Bridge and chained themselves to 55-gallon drums filled with cement across Interstate 880 in Oakland. Protesters marching into Brooklyn blocked Manhattan-bound traffic on the Brooklyn Bridge.