A US citizen had battery acid thrown in his face by a man who told him to "go back to [his] country" in an incident Milwaukee police are treating as a hate crime.

Mahud Villalaz, 42, who immigrated from Peru and has lived in the United States for 19 years, suffered second degree burns from the attack.

On Sunday, two days after the attack, police arrested a 61-year-old suspect in connection with the incident but are still searching for the perpetrator, according to the Milwaukee Journal Sentinel.

The confrontation began when Mr Villalaz parked in a bus lane near the Mexican restaurant where he was planning to have dinner.

A strange man approached him and told him it was illegal to park in that space. According to Mr Villalaz, the man’s comments became increasingly anti-immigrant.

According to the Journal Sentinel, the man asked him why he came to "invade [his] country".

Mr Villalaz says he moved his car and went back towards the restaurant where the man was waiting with an open metal bottle.

He told the man he was a US citizen. "I think I p***ed him off because I told him, 'This is my country. This isn’t your country. Everybody came from somewhere else here,'" Mr Villalaz told WISN.

It's then that he says the attacker threw battery acid in his face.

Mr Villalaz was treated at a hospital overnight and released on Saturday.

Hate crimes have been on the rise in the US over the past five years. Some experts believe the divisive, racist rhetoric often used by Donald Trump such as describing Mexicans as “rapists”, is tied to the surge in hate crimes.

Mr Villalaz spoke at a news conference over the weekend after being released from the hospital. "I feel scared being an American citizen. I feel scared that I cannot feel protected in my own country with my neighbours.”

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