NEW YORK —Civil rights lawyers sued the U.S. Commerce Department last week to try to stop plans to add a citizenship question to the 2020 Census, calling it an unconstitutional attempt to discriminate against immigrants.

The Manhattan federal court lawsuit on behalf of immigrants’ rights groups blames racial animus for the recent announcement that the Census will include a citizenship question for the first time since 1950.

The lawsuit, filed by the American Civil Liberties Union and others, claims the question intentionally discriminates against immigrants and will increase fear in their communities. It alleges Census participation will be depressed, diluting the economic and political power of residents in places like New York City; Prince Georges’ County, Maryland; Houston and San Antonio, Texas and the Florida counties of Miami-Dade, Broward and Orange.

The lawsuit predicts the citizenship question will result in at least two states losing a congressional seat. It alleges that the question was added unconstitutionally with discriminatory intent to diminish the political power and influence of Latinos, Asian-Americans, Arab Americans and immigrant communities of color generally.

U.S. Commerce Secretary Wilbur Ross announced the plan in March, saying the question was needed in part to help the government enforce the Voting Rights Act, a 1965 law meant to protect political representation of minority groups. The Commerce Department is responsible for the Census.

The plan has resulted in several lawsuits, including one in California, the nation’s most populous state with the highest concentration of foreign-born residents, and another in New York brought by 17 Democratic attorneys general, the District of Columbia, six cities and the bipartisan U.S. Conference of Mayors.

The decennial Census is required by the Constitution and used to determine the number of seats each state has in the House of Representatives, as well as how federal money is distributed to local communities.

The Justice Department did not immediately respond to a request for comment.

Donna Lieberman, head of the New York Civil Liberties Union, said in a release that President Donald Trump’s administration was, “shamelessly weaponizing the Census to wage its war on communities of color, immigrants and the poor.

“New Yorkers refuse to be under counted, discriminated against or driven into the shadows,” she added.

Steven Choi, executive director of the New York Immigration Coalition, said the citizenship question, “is toxic to New York’s four million immigrants and all New Yorkers, who stand to lose millions of dollars in federal aid and representation in Congress.”

Plaintiffs in the lawsuit include the coalition, the American-Arab Anti-Discrimination Committee and other groups. Besides the Commerce Department and Ross, the Bureau of the Census and its director, Ron Jarmin, were also named as defendants.