Protesters at Portland International Airport in Oregon attacked a Donald Trump supporter on Sunday, knocking him unconscious after repeatedly hitting him in the head.

Protests have broken out at airports across the U.S. over the past few days after President Trump signed an executive order temporarily halting refugees and citizens of seven Muslim-majority countries from entering the country over terrorism fears.

Grant Chisholm, 39, of Portland, Ore. was at the airport with three other members of the group Bible Believers for a counter-protest on Sunday.

During the protest, Chisholm was hit in the head three times "with something metallic" by one of the demonstrators protesting against Trump, the Oregonian reported.

The incident was caught on video and uploaded to Facebook by the group Women for Trump Movement. The video shows Chisholm falling to the ground after another man appears to punch him in the head.

After Chisholm falls to the ground, two men lean over him to protect him from further blows to the head, the video shows. Eventually security appears to manage the situation.

In the background of the video, some protestors can be heard shouting "Peace" while others taunt an unconscious Chisholm.

One protester can be heard calling Chisholm a "Nazi Boy" and another man can be heard yelling "your boy got knocked out."

"They almost killed me tonight," Chisholm told the Oregonian.