President Donald Trump and Republican leaders are facing pushback from within their party over a proposed $1 billion in Secret Service funding tied in part to White House security upgrades, including a controversial ballroom project.

Some GOP senators and House members are questioning the scope, cost, and justification of the spending, with several demanding more details before supporting it.

While the White House argues the funds are needed after recent security incidents and threats against Trump, critics say taxpayer money should not be used for what they view as a private or unnecessary project.

Senate leaders, including Majority Leader John Thune, are working to secure enough votes to pass the broader package, though a few Republicans—such as Senators Rand Paul and Lisa Murkowski—remain skeptical or opposed, Politico has reported.

Democrats are also preparing to challenge the provision as an improper budget addition, adding further uncertainty to the bill’s fate.