House Democrats, citing “substantial unplanned costs,” have asked President Trump to change his plan to hold a July 4 event at the Lincoln Memorial.

Three top Democrats, led by Majority Leader Steny Hoyer, D-Md., wrote to Trump that they are “deeply troubled” by Trump’s plan to have the Interior Department facilitate the event. It would take place on the same day as the massive July 4 celebration and fireworks at the National Mall, which draws thousands of people.

“To add yet another event on the Mall, with the President of the United States in attendance, will create substantial unplanned costs without Congressional review,” said the letter to Trump, from Hoyer, Rep. Betty McCollum, D-Minn., who is chairwoman of the House Appropriations panel that oversees the National Mall's annual budget, and Rep. Raúl Grijalva, D-Ariz., chairman of the National Resources Committee.

The group also noted to Trump that the July 4 celebration on the National Mall “has been non-partisan and apolitical,” and Trump’s “conflicting event…could create the appearance of a televised, partisan campaign rally on the Mall at public expense.”

Trump is planning to speak at the event, he told his Twitter followers earlier this year.

“HOLD THE DATE! We will be having one of the biggest gatherings in the history of Washington, D.C., on July 4th. It will be called “A Salute To America” and will be held at the Lincoln Memorial. Major fireworks display, entertainment and an address by your favorite President, me!” Trump tweeted.

The Democrats also warned that Trump’s event could pose a safety threat because the president would require significant security that they said, “could severely inhibit access to and egress from our nation’s capital for tens of thousands of visitors hoping to attend."

Finally, the group warned Trump the cost of the event could significantly deplete the Interior Department’s budget, which could force it to reduce costs in other areas “such as visitor services or facilities operation and maintenance.”