WASHINGTON (AP) — The House Oversight Committee sued two top Trump administration officials Tuesday for refusing to produce documents related to a decision to add a citizenship question to the 2020 census.

Attorney General William Barr and Commerce Secretary Wilbur Ross "have not produced a single additional document" since the Supreme Court blocked the administration's efforts to include the citizenship question last June, the committee said.

Rep. Carolyn Maloney, D-N.Y., who was elected oversight chair last week, said the lawsuit follows the example set by the panel's late chairman, Maryland Rep. Elijah Cummings.

Cummings, who died in October, "believed with all his heart that the Constitution requires Congress to ensure that the rapidly approaching Census is conducted in a professional manner that promotes accuracy, ensures integrity and is free from partisan politics — and I couldn't agree more,'' Maloney said.

The lawsuit marks the latest action by Democrats to use their House majority to aggressively investigate the inner workings of the Trump administration, including a House vote in July to hold Barr and Ross in contempt of Congress over the census issue.

Oversight also is one the House committees leading an impeachment inquiry of President Donald Trump.

Trump abandoned the citizenship question last summer after the Supreme Court said the administration's justification for the question "seems to have been contrived." Trump directed agencies to try to compile the information using existing databases.

A Commerce Department spokeswoman said the lawsuit lacks merit and said Commerce has cooperated in good faith with the Oversight Committee.

The department has made over 2,000 documents available to the committee since January and submitted hundreds of pages of additional documents since the Supreme Court's decision, the spokeswoman said. Current and former officials participated in transcribed interviews, and Ross testified before the panel for seven hours, she said.

Maloney said the committee continued its investigation in recent months, even as Cummings' health declined, and has obtained new documents and information from other sources.

Lawmakers need the documents being withheld by Justice and Commerce, in part, to determine whether Congress should take emergency action to protect the census from partisan political interference, she said.

In a related development, a liberal advocacy group also filed suit Tuesday, claiming the Census Bureau has "drastically and arbitrarily" underfunded the 2020 census, jeopardizing accurate counts of African Americans, Latinos and other minority groups.

The suit, filed by the nonprofit Center for Popular Democracy, charges that the Census Bureau has refused to spend more than $1 billion in appropriated funds, despite a congressional directive to spend the money to avoid an undercount.

The New York-based group champions worker and immigrant rights.

The census is set to begin in Alaska in January and across the country in April 2020.