Updated at 3:30 p.m. Monday

Portland International Airport was packed Sunday with hundreds demonstrating against the executive order banning immigration from seven Muslim-majority countries signed by President Donald Trump last week.

Port of Portland officials say approximately 600 turned out, eclipsing the previous day's 100 to 150 demonstrators.

The presence of a four-man counter-protest at times turned tense as demonstrators from both camps clashed. One of the counter-demonstrators was assaulted just after 5 p.m., Port of Portland spokesman Steve Johnson said.

Grant Chisholm, 39 of Portland told The Oregonian/Oregonlive that he was at the airport with three other members of the group Bible Believers for a counter-protest when a Trump opponent hit him in the head three times with something metallic. Chisholm dropped and drifted in and out of unconsciousness, he said, while vomiting as other protesters kicked him in the head.

"They almost killed me tonight," Chisholm said.

A thee-minute video posted on a Facebook site called "Women for Trump Movement" shows a man falling to the ground inside the terminal after another man punches him in the head. People immediately circle the man on the ground and appear to keep the shouting crowd at bay. Police eventually arrive to control the throng. The man stirs and raises his hand for help as some people chant: "Peaceful protest."

Another video sent to The Oregonian/OregonLive shows the counter-protesters surrounded in a mutual shout-off at one point outside the airport terminal when at least two of the counter-protesters take down a demonstrator by the hair.

The demonstration began at the Southwest Airlines kiosk at the terminal at 2 p.m., where about 300 people gathered. It was one of several such gatherings throughout the country protesting the president's executive order.

After a few minutes of chanting, they exited to a "free speech zone" just outside the terminal at the passenger drop-off area.

Airport personnel diverted traffic for an hour while protesters chanted outside the terminal. Rabbi Joseph Wolf of Havorah Shalom was among the crowd.

When he heard Trump signed the executive order, Wolf said he "got a pit in my stomach."

"It hurt. Every hour this week it was something -- but this was like a knife," he said.

We're at Portland International Airport for the second day of the #nobanpdx protest against Donald Trump's executive order on immigration. Posted by The Oregonian on Sunday, January 29, 2017

What made it worse, Wolf said, was the timing of the administration's decree. Trump signed the executive order on International Holocaust Remembrance Day.

"It's hard for me to talk about it without tears. It's personal," he said.

U.S. Sen. Jeff Merkley, Rep. Suzanne Bonamici and Portland Mayor Ted Wheeler gave short speeches, with mixed results.

Those gathered cheered for Merkley and Bonamici, who pledged to fight Trump on the ban as well as the confirmation of Betsy DeVos as education secretary. But when Wheeler took the bullhorn to pledge a commitment to keep Portland a sanctuary city, he was immediately shouted down by members of the crowd.

Portland's Resistance member Luis-Enrique Marquez started to chant "you lie" as Wheeler spoke. Marquez told The Oregonian/OregonLive that it was disingenuous for the mayor to speak in support of protesters when a week earlier he had given Portland police the go-ahead to break up Inauguration Day demonstrations.

"Mayor Wheeler will not let us out in the streets without a $3,000 permit -- the same thing he's out here with us for," Marquez said.

Shortly afterward, a series of shouting matches broke out between the four men staging the counter-protest and a group of anti-Trump demonstrators.

The men said they were there to offer a different viewpoint, claiming they were concerned about Syrian refugees entering the country and accusing the anti-Trump demonstrators of embracing terrorists.

The counter-demonstration followed the group of hundreds inside, later taking refuge on a balcony as the two groups attempted to out-shout each other near the Made in Oregon store.

After about an hour, the counter-protesters moved on as the larger crowd made its way through the airport. Security agents blocked off concourses A, B and C as the march moved on.

The throng moved through the airport in a loop, eventually making its way to baggage claim. Once there, demonstrators spilled into the street and temporarily blocked traffic.

That was at about 5 p.m.

Soon after, a scuffle broke out between the four counter-protesters and anti-Trump demonstrators, which resulted in the assault of Chisholm.

Chisholm said he's been to many protests to preach and has been hurt before. He said one man in particular became aggressive, asking to fight. Chisholm said police in riot gear swarmed the area to pull the protesters apart. Portland police spokesman Pete Simpson confirmed that the agency assisted in crowd control, using an FN 303 riot gun after the assault.

Police put Chisholm in an ambulance for Legacy Emannuel Medical Center. He was released about two hours later. He said he suffered a concussion but is fine.

Port officials are collecting information on the incident. There were no arrests, Johnson said.

The interruption didn't faze those gathered -- a crowd approximately 200 strong kept chanting just outside the United Airlines kiosk at the terminal before heading back for another tour of the airport.

The protest ended just before 6 p.m. as Portland Resistance leader Gregory McKelvey addressed the crowd, suggesting demonstrators walk to the MAX station in a group.

Reporter Lynne Terry contributed to this story.

--Eder Campuzano

503.221.4344

@edercampuzano

ecampuzano@oregonian.com