California’s House Republicans have penned a letter to President Donald Trump asking him to block a pending $650 million federal grant for California’s troubled high-speed rail project until an audit of the project’s finances is completed.

“Providing additional funding at this time to the authority would be an irresponsible use of taxpayers dollars,” a portion of the letter, which was obtained by the Los Angeles Times, reads. It continues, “In light of the new revelations from the confidential FRA report, we request no further monies be granted to the [California High-Speed Rail] Authority or the state of California for high speed rail until a full and complete audit of the project and its finances can be conducted and those finding be presented to the public.”

According to the Times, the letter was signed by all 14 members of California’s GOP delegation, including House Majority Leader Kevin McCarthy, and was sent to Trump’s Transportation Secretary Elaine Chao on January 24.

The Los Angeles Times indicates that a new, confidential report on the high-speed rail has found that it could cost taxpayers more than double than what was originally estimated (approximately $3.6 billion more).

California Lieutenant Gov. Gavin Newsom, who is a candidate for the 2018 gubernatorial race, flip-flopped and announced in October that he now supports California’s $64 billion high-speed rail system, after opposing it and withdrawing support for the controversial project just two years ago.

The Democrats countered the Republicans’ letter with their own.

According to the Times, the letter not only asked that the multi-million dollar federal grant be approved, it charged that the Republicans’ letter was riddled with “inaccuracies and innuendo.” A spokesman for House Minority Leader Nancy Pelosi (D-CA) reportedly issued a statement Monday arguing that blocking the train would coset California thousands of jobs.

Her office also reportedly said it was “unfortunate” that the Republicans, by sending their letter, “chose to take Caltrain electrification hostage.”

Follow Adelle Nazarian on Twitter and Periscope @AdelleNaz