WASHINGTON, D.C. — Democrats on the Senate Appropriations Committee are asking the Government Accountability Office to investigate the costs of President Donald Trump’s Independence Day celebration and examine whether the spending is legal.

Appropriations ranking member Patrick J. Leahy of Vermont, Tom Udall of New Mexico and Chris Van Hollen of Maryland want the GAO to provide a comprehensive cost estimate for all the events, including Trump’s “Salute to America,” which was the subject of criticism for its incorporation of military equipment, potential high cost and the possibility for an apolitical holiday event to be politicized.

The Fourth of July celebration in Washington, D.C., also included the National Independence Day Parade, A Capitol Fourth concert and the National Park Service fireworks display, all of which have taken place in the past. The lawmakers want separate accounting for each of the four events.

The letter was sent on July 5 to Gene Dodaro, GAO’s comptroller general. The Senators said that the decision for the National Park Service to divert almost $2.5 million in entrance and recreation fees to help pay for the Independence Day celebration is of concern to them.

“Congress did not specifically provide funds to cover the costs of the President’s expanded Fourth of July events, and we are very concerned by the impacts and the precedent of diverting limited Federal resources —including the use of military personnel, equipment and aircraft as well as other appropriations or visitor fees paid to improve national parks —to organize and execute unbudgeted events,” the senators wrote in their letter.

Leading up to the Fourth of July, the senators wrote to Interior Secretary David Bernhardt asking for information about the added costs to put on this years’ Fourth of July celebration, but he did not respond to the letter by the June 28 deadline, according to the Democrats’ release.

In addition to Leahy’s position as vice chairman of the full committee, Udall is the ranking member on the subcommittee on the Interior, Environment and Related Agencies, and Van Hollen serves on that same subcommittee.

“Further, we are troubled by reports that preferential access to the National Mall was organized by political entities such as the Republican National Committee, which furthers the appearance that taxpayer funds were used to accomplish political objectives,” they wrote.

Tickets closest to the Lincoln Memorial, where Trump gave his speech on the Fourth of July, were distributed by the White House to Republican donors and political appointees.