The Justice Department on Friday asked a federal judge to halt proceedings in a lawsuit involving President Trump’s private business, arguing that allowing the case to go forward would “be a distraction to the President’s performance of his constitutional duties.”

The lawsuit, filed by Maryland and the District of Columbia, centers on whether Trump is violating the Constitution by continuing to do business with foreign and state governments while serving as president. Earlier this year, U.S. District Judge Peter J. Messitte ruled that the historic case could proceed, opening the door for the plaintiffs to seek internal records from Trump’s hotel in downtown Washington.

In Friday’s filing, the Justice Department sought to block the case on the grounds that Messitte was setting new precedent on complex issues involving a sitting president and asked that he put the case on hold until a higher court could review his rulings.

“Plaintiffs are now poised to attempt to conduct civil discovery against the sitting President, in his official capacity, which necessarily would be a distraction,” Justice Department attorneys wrote in the 36-page filing.

This sort of appeal is rarely granted, because lower court judges usually prefer to complete a full case before any appeal is made. Messitte likely will not decide until October about at the earliest.

In the meantime, the judge must also decide whether to allow other parts of the case to proceed.

D.C. Attorney General Karl A. Racine (D) and Maryland Attorney General Brian E. Frosh (D) filed the case last year, arguing that by accepting business from foreign governments and state officials, particularly at the Trump International Hotel in Washington, Trump was violating the Constitution’s clauses barring elected officials from receiving emoluments — meaning gifts or payments — from foreign or state governments.

The attorneys general argue that the process of seeking documents and conducting interviews to obtain information related to the D.C. hotel ought to proceed. In other legal filings this week, they indicated they expected they would need six months to search records from the hotel and identify relevant transactions with governments, both foreign and American.

Part of the case earlier this year hinged on the definition of the term emoluments, as the clauses have been rarely tested in the courts. In July, Messitte rejected the Justice Department’s interpretation that the Constitution’s framers meant to bar presidents from taking bribes and outright gifts. Messitte ruled that the word encompassed a bigger universe of payments, including transactions conducted at fair-market value.

Messitte narrowed the scope of the case to Trump’s D.C. hotel, which is in the federally owned Old Post Office, under a lease his company has with the General Services Administration.

The Trump Organization, which the president still owns, has given few details about its transactions with foreign governments. But at least five foreign governments held events or booked large blocks of rooms at Trump’s D.C. hotel.

Staff writers Ann E. Marimow and David A. Fahrenthold contributed to this report.