Two dozen Latino and Asian-American organizations filed a federal lawsuit Thursday alleging that the Trump administration's plan to add a citizenship question to the 2020 census violates the U.S. Constitution because it's racially discriminatory.

The lawsuit filed in U.S. District Court in Maryland by the Mexican American Legal Defense and Educational Fund and Asian Americans Advancing Justice claims the decision to add a question asking people if they are U.S. citizens is motivated by racial animus.

The groups say the question is intended to severely undercount minorities and immigrants, and to dilute their political representation and federal funding to their communities.

The Justice Department has said reinstating the question "will allow the department to protect the right to vote and ensure free and fair elections for all Americans."

U.S. Commerce Secretary Wilbur Ross announced in March that the census distributed to every U.S. household will include a citizenship question for the first time since 1950.

Ross said then that the question was needed in part to help the government enforce the Voting Rights Act, the 1965 law that was intended to protect the political representation of minority groups. Ross said it will provide a more accurate tally of voting-eligible residents than is currently available from a smaller sampling survey that includes the citizenship question.

But critics say the question will drive down already low census response rates among immigrants, reduce their political representation and rob their communities of federal money.

Several other lawsuits have been filed challenging the citizenship question, including in New York and California, but this is the first believed to make a racial discrimination claim, said Thomas Saenz, MALDEF's president and general counsel.

"We think there are good grounds for arguing and concluding that this was motivated specifically to target the Latino community and the Asian-American community and to reduce their counts," Saenz said.

The U.S. Department of Commerce and the U.S. Census Bureau are named as defendants in the lawsuit. Spokespeople for the agencies did not immediately respond to requests for comment.