“I don’t think anybody in America wants people to starve to death,” Mr. Reese said. “But if you want to help somebody, people can go to McDonald’s or Kentucky Fried Chicken and give them a meal.”

He said that the police would ignore “isolated cases” of violating the ordinance, and predicted that the law would ultimately help the homeless because they would be forced to seek meals at soup kitchens run by social service organizations that could provide other assistance as well.

But Maria Foscarinis, director of the National Law Center on Homelessness and Poverty in Washington, said the prohibition would do more harm than good. “Nobody wants the poor and homeless living in public spaces,’’ Ms. Foscarinis said, “but this kind of response is terribly misguided.”

The American Civil Liberties Union of Nevada, which opposed the ordinance, said it was preparing a legal challenge. The group’s general counsel, Allen Lichtenstein, called the measure absurd and said it was an unconstitutional infringement on free assembly and other rights.

Mr. Lichtenstein accused Mayor Oscar B. Goodman, who supports the new restriction, of waging a campaign against homeless people, whom the mayor has openly criticized. At a June meeting of the City Council, Mr. Goodman suggested that panhandlers with signs asking for food be sued for “false advertising” because soup kitchens provide free meals. “Some people say I’m the mean mayor,’’ Mr. Goodman acknowledged, but he defended the ordinance as part of the effort to steer the homeless to social service groups, and said the city was taking part in a regional initiative to end homelessness in 10 years.

The ordinance, an amendment to an existing parks statute approved by the Council on July 19, bans the “the providing of food or meals to the indigent for free or for a nominal fee.” It goes on to say that “an indigent person is a person whom a reasonable ordinary person would believe to be entitled to apply for or receive” public assistance.

Image Recipients of Ms. Saccos handouts say that they are far from shelters and that they get little public assistance. Credit... Monica Almedia/The New York Times

Violating the ordinance is a misdemeanor, and can be punished by a fine of up to $1,000 or a jail term of up to six months, or both. Diana Paul, a spokeswoman for the city, said the police would begin enforcing it after briefings from city lawyers.