A group of Republican senators is threatening to withhold support for funding the government by a Friday shutdown deadline unless they get a vote on defunding remaining federal vaccine mandates — renewing a stand they took ahead of the last deadline in December.

In an open “Dear Colleague” letter on Monday, Sens. Mike Lee of Utah, Roger Marshall of Kansas, Cynthia Lummis of Wyoming, Mike Braun of Indiana, Rand Paul of Kentucky, and Ted Cruz of Texas stated their intention to oppose a stopgap government funding measure unless their demands are met.

“We will continue to stand against these mandates until they are discontinued in ambition, design, and practice,” the senators wrote. “For that reason, we are writing to let you know that we will not consent to a time agreement that eases passage of the Continuing Resolution (‘CR’) now before the Senate absent an agreement to allow for a roll call vote on an amendment that defunds the enforcement of these vaccine mandates for the spending period covered by the CR.”