A federal immigration officer refused to show an arrest warrant and shoved a criminal defense lawyer as he tried to step on an elevator with his client on the fourth floor of the Multnomah County courthouse Friday morning.

Courthouse arrests involving immigrants have drawn intense criticism from civil rights advocates and court employees across the nation. Critics say the arrests discourage defendants, witnesses and victims from coming to court. U.S. Customs and Enforcement agents routinely refuse to show warrants, a tendency that spurred New York to issue new requirements last week that mandate judicial warrants for courthouse arrests.

Those tensions flared up in Oregon April 26, when ICE officers clashed with a Portland defense attorney.

John Schlosser had been in court representing a man who was in a deferred sentencing program that would allow a misdemeanor harassment charge to be dismissed. As he and his client left Judge Melvin Oden-Orr's courtroom, several men in plainclothes approached them.

The men, wearing U.S. Immigration and Customs Enforcement badges around their necks, detained Schlosser's client. Schlosser asked to see a warrant or other proof that the ICE agents had detained the correct person. The officers refused to show any documents to the lawyer, but said they were seeking a man named Bernabe DeJesus.

Schlosser declined to confirm that DeJesus was his client, but a man by that name had been scheduled to appear in Oden-Orr's courtroom for a status check on a misdemeanor harassment charge.

ICE officials did not immediately return WW's request for comment on the incident. In the past, ICE officials have said the agency resorts to courthouse arrests when officers have tried, but failed, to arrest people elsewhere.

After the officers detained his client, Schlosser says he followed the officers to the elevators and tried to ride down to the first floor with the men.

"For our security, you're not boarding," an ICE officer told Schlosser as the men entered the courthouse elevator.

"Yes, I am," Schlosser says as he edges closer to the elevator. The agent blocked his path.

"No, you're not," he says. "For our security you're not."

"This is a public building," Schlosser says. "You have no authority here. I'll keep my hands to myself, but you can't stop me from getting on this elevator."

"I am," the officer said.

That's when, video shows, the unidentified ICE agent shoved Schlosser.

"He shoved me hard in the chest and knocked my wind out," Schlosser tells WW.

Another ICE officer can be heard in the video immediately after the shove telling his partner to "calm down." The officer who pushed Schlosser tells him he's impeding a federal arrest, but eventually allows him to ride the elevator to the first floor.

Schlosser says he informed Presiding Judge Stephen Bushong and Chief Criminal Judge Cheyrl Albrecht about the incident. He says he reported the physical altercation to the Multnomah County Sheriff's Office.

The incident is just the latest flashpoint between immigration officials and the Oregon criminal justice system.

For more than two years, ICE has been increasingly turning to courthouses to pick up undocumented immigrants who may be subject to deportation.

During that time, local ICE officials have frequently expressed frustration and contempt for Oregon. In internal emails, they complain that local law enforcement agencies do not comply with detainer requests, which are unconstitutional in Oregon, and one officer called the state a "liberal dumpster."

Extensive public records released to WW and the American Civil Liberties Union of Oregon show that immigration officials have planned hundreds of arrests at courthouses across Oregon.

"We know that ICE is frequently and consistently using our state courthouses to target immigrants for arrest and these arrests are taking place across the state, in or around at least 15 different courthouses in the state of Oregon," says Leland Baxter-Neal, an ACLU staff attorney.

Baxter-Neal says the arrests have a "chilling and deterring effect" on defendants, who may be innocent, appearing in court to fight criminal charges.

Whitney Phelps, who works for the Metropolitan Public Defenders, says criminal defense attorneys worry that potentially exculpatory witnesses may not come to court because ICE agents have been arresting people. That could lead to wrongful convictions, she says.

Phelps says the arrests often traumatize the people who see them because they do not resemble traditional arrests by police or sheriff's deputies. ICE officers rarely wear uniforms, display badges or show arrest warrants.

"Most people who witness those kinds of arrests would say it's more of a kidnapping than an actual arrest," Phelps says. "It does seem like some random stranger is grabbing a person off the street and putting them in the back of a car and driving away."

She says she's concerned by Friday's altercation because she has advised public defenders to ask the same questions Schlosser did if ICE officials try to arrest a client.

"I'm shocked and pretty horrified to hear that an attorney who was trying to defend his client's rights was mistreated so severely," Phelps says.

Local immigration advocates say justice is being corrupted when ICE agents pursue arrests at courthouses.

"Our community deserves to access the justice system in Oregon without fear of being harassed or detained, or having their attorney physically attacked by federal immigration officers in our courthouses," says Andrea Williams, executive director at Causa. "We fear that our local courts serving victims, defendants, parents, and children are being unfairly commandeered by federal immigration for its own motives, putting all in harm's way."

UPDATE (April 28, 9:45 a.m.): ICE officials say Schlosser interfered with an arrest.

"On April 26, ICE deportation officers were at the Multnomah County Courthouse to execute an arrest warrant on Bernabe Lopez-Dejesus, a Mexican citizen, who is illegally present in the United States," says ICE spokeswoman Tanya Roman.  "During the arrest, Lopez-DeJesus' criminal attorney attempted to impede the lawful arrest. By impeding a federal officer while they were engaged in their official duties, the attorney put himself, his client, the agents involved and the community at risk. These type of actions are unprofessional, unacceptable, and may be violate criminal laws."