Federal agents with the U.S. Immigration and Customs Enforcement's (ICE) Homeland Security Investigations (HSI) detain a man in this handout picture taken in Dallas, Texas March 30, 2014 and released May 1, 2014. Reuters

City officials warned New York City residents this week to watch out for a group of scammers who were posing as U.S. Immigration and Customs Enforcement agents while trying to swindle undocumented immigrants. The scammers were asking people to hand over money, and said if they refused to do so, they'd be immediately deported.

"If someone is a victim of fraud, they need to report it right away so we can get the person who did this to them and stop them from victimizing others," Mayor Bill de Blasio said.

Most recently, a man in New York City's Queens borough was stopped and threatened with deportation if he did not pay the imposters, City Council Majority Leader Jimmy Van Bramer (D-Queens) said Tuesday. Four men wearing Immigration and Customs Enforcement jackets approached the unidentified man Monday afternoon near his home, according to the New York Daily News. The men demanded all the man's cash and said he would be arrested and deported if he didn't pay up.

"He gave them all his cash, $250," Van Bramer said.

The man’s wife called Van Bramer’s office shortly after the incident to file a report. The victim’s immigration status was unclear.

Van Bramer joined immigration attorneys and advocates Tuesday night at a rally near the site of the alleged fraud. “We want to let people know that regardless of your status, this is illegal, and no officer, no federal officer, no ICE officer would demand payment,” Van Bramer said.

Monday’s incident comes after federal agents arrested undocumented immigrants across the nation last week in their homes as well as their workplaces. In the last week alone, ICE raids resulted in the arrest of 700 immigrants, according to ABC 7. Officials said the immigrants all had criminal records.

In the New York City metropolitan area, 40 undocumented immigrants were arrested, most of whom were allegedly criminals. New York City is a sanctuary city, meaning if a victim reports a crime, the police are not allowed to ask about their immigration status or report them to federal agents.