Authorities in Illinois are investigating a case on Sunday in which a US citizen was detained by federal immigration agents before ending up at a hospital with injuries.

It came the same day that Immigration and Customs Enforcement (ICE) shot and seriously wounded a man in Austin, Texas.

Police in the Chicago suburb of Evanston said in a statement that officers were called to an argument between two men just before 10am on Sunday and arrived to find a man on the ground with injuries to his head, neck, and teeth, surrounded by several people who were assisting him.

Officers questioned a man in one of two SUVs who was wearing plainclothes and a vest with the word “police” on it. That person “identified himself as a federal agent conducting a fugitive investigation”, the statement said.

“The agent told the officer that agents had attempted to identify an individual who resembled a person they were seeking,” the statement added. “He said the individual refused to provide identification, was detained for fingerprinting, and resisted detention.

“Agents later determined he was not the person they were seeking and learned that he was a US citizen. He was released.”

An officer saw blood on the agent’s hands, the statement also noted, and he said he was injured “while attempting to handcuff the individual”.

The statement did not specify which agency the person said he was from. But witnesses told police they believed the persons attempting to arrest the individual were ICE agents.

The agent who spoke to the officer said five federal agents had been operating in the area in separate unmarked vehicles and said they had a warrant for the arrest of a person with a Chicago address.

“The agent also said the federal agents left the area after protesters began to gather because they feared they would be attacked,” the statement said.

Officers later contacted the wrongly detained person, an adult Evanston resident, at a hospital and “photographed and documented his injuries”.

The US Department of Homeland Security (DHS), which oversees ICE, did not immediately respond to a request for comment.

The episode came as ICE is facing increasing scrutiny over its violent tactics in support of the immigration crackdown that Donald Trump has pursued throughout his second presidency.

A 28-year-old Venezuelan man remained hospitalized in Texas in a serious but stable condition on Sunday night after he was shot earlier in the afternoon during an encounter with federal agents in Austin.

The shooting followed a traffic stop in the city’s north side. A lawyer for the victim said he was making a DoorDash delivery when he was shot.

Austin’s Democratic mayor, Kirk Watson, said he wanted the city’s police department involved in the investigation to provide “clear, third-party eyes”.

The incidents follow a ramping up of Trump’s federal immigration crackdown, which saw a record 50,000 people arrested in July. More than half had no criminal record, despite the Trump administration’s pledge to focus the crackdown on dangerous criminals, according to the Deportation Data Project.

Also in July, an ICE officer fatally shot 52-year-old Lorenzo Salgado Araujo of Houston, after federal agents driving unmarked vehicles pursued him while he was taking his construction crew to a job site.

Among others to be fatally shot by federal agents under the command of the Trump administration were US citizens Renee Good and Alex Pretti days apart in January in Minneapolis.