Oklahoma’s Republican governor and the state attorney general filed a federal lawsuit on Thursday, challenging the Defense Department's COVID-19 vaccination mandate on the Oklahoma National Guard.

In a statement, Gov. Kevin Stitt argued that the Biden administration's defense secretary, Lloyd Austin, overstepped his constitutional authority by subjecting the National Guard to the mandate, which applies to active-duty military members.

“This week, Secretary of Defense Lloyd Austin declared his intention to proceed with unconstitutional punishment that individually targets Oklahoma National Guard soldiers and airmen, including withholding their pay," Stitt said.

FILE-  Oklahoman Gov. Kevin Stitt looks back at the needle after looking away while being administered the Johnson & Johnson vaccine following a news conference about opening vaccine eligibility on March 29, 2021, in Oklahoma City. Oklahoma's Republican governor and the state attorney general are suing in federal court to exempt the state's National Guard from a Biden administration COVID-19 vaccine mandate. Stitt argued in a statement Thursday, Dec. 2, 2021, that the Biden administration's Defense Department overstepped its constitutional authority by subjecting the National Guard to the mandate it imposed on the active-duty military.  (AP PhotoSue Ogrocki, File)

FILE- Oklahoman Gov. Kevin Stitt looks back at the needle after looking away while being administered the Johnson & Johnson vaccine following a news conference about opening vaccine eligibility on March 29, 2021, in Oklahoma City. Oklahoma's Republican governor and the state attorney general are suing in federal court to exempt the state's National Guard from a Biden administration COVID-19 vaccine mandate. Stitt argued in a statement Thursday, Dec. 2, 2021, that the Biden administration's Defense Department overstepped its constitutional authority by subjecting the National Guard to the mandate it imposed on the active-duty military. (AP PhotoSue Ogrocki, File)

The Pentagon couldn't immediately be reached for comment Thursday on the lawsuit.

Stitt had asked Austin to suspend the mandate for the Oklahoma National Guard and directed his new adjutant general to assure members that they would not be punished for not being vaccinated.

However, Austin rejected that exemption and said any National Guard members not vaccinated against COVID-19 would be barred from federally funded drills and training required to maintain their Guard status.

Stitt said that although National Guard members are paid by the federal government, he remains their commander in chief under federal and state constitutional and statutory law unless the president orders their mobilization.