The City of New York says it may fine individuals up to $US250,000 ($NZ400,000) if they use the term "illegal alien" in a derogatory way.
"BREAKING: New York City has made it illegal to threaten to call ICE based on a discriminatory motive or to tell someone 'go back to your country'. Hate has no place here," the New York City Commission on Human Rights tweeted last week.
New York City Mayor Bill de Blasio, who pulled out of the Democratic presidential race earlier this month, tweeted, "If you want to come into the ultimate city of immigrants and try to spread hate, you WILL face the consequences."
In the media release, the commission said it was releasing "new legal enforcement guidance that defines discrimination on the basis of perceived or actual immigration status and natural origin under the New York City Human Rights Law" in the workplace, housing and public spaces such as stores, hospitals and movie theatres.