FRANKFORT, Ky. (AP) — Kentucky's attorney general won a preliminary court order Tuesday to block President Joe Biden's coronavirus vaccination mandate for federal government contractors and subcontractors.

The preliminary injunction issued by U.S. District Judge Gregory F. Van Tatenhove stops the mandate from taking effect in Kentucky, Tennessee and Ohio.

"This is a significant ruling because it gives immediate relief from the federal government's vaccine requirement to Kentuckians who either contract with the federal government or work for a federal contractor," Kentucky's Republican attorney general, Daniel Cameron, said in a statement.

Ohio and Tennessee joined in filing the lawsuit, which claims the vaccination requirement is unlawful and unconstitutional. The mandate requiring employees at federal contractors to get vaccinated against COVID-19 has been set to take effect on Jan. 4.

"This is not a case about whether vaccines are effective. They are," Van Tatenhove wrote. "Nor is this a case about whether the government, at some level, and in some circumstances, can require citizens to obtain vaccines. It can.

"The question presented here is narrow," he said. "Can the president use congressionally delegated authority to manage the federal procurement of goods and services to impose vaccines on the employees of federal contractors and subcontractors? In all likelihood, the answer to that question is no."