WASHINGTON

US President Joe Biden opposes the removal of the military's ongoing COVID-19 vaccine mandate, the White House said on Monday as lawmakers take up a key defense spending bill.

Congress is currently weighing whether it will add the vaccine repeal to the annual National Defense Authorization Act (NDAA), but National Security Council spokesman John Kirby told reporters that Biden opposes any such change.

"Secretary Austin's been very clear that he opposes the repeal of the vaccine mandate and the president actually concurs with the secretary of defense. He continues to believe that all Americans, including those in the armed forces, should be vaccinated and boosted for COVID-19," Kirby said during a virtual press briefing, referring to Defense Secretary Lloyd Austin.

"This remains very, very much a health and readiness issue for the force. Again, (the) president supports Secretary Austin's opposition to a repeal of the mandate," he added.

The $800 billion defense act is still winding its way through Congress, with lawmakers hashing out key disagreements and adding amendments, potentially including the vaccine mandate repeal, to the sprawling piece of legislation.

Republicans have been championing the effort, and House Minority Leader Kevin McCarthy claimed on Sunday that Congress had worked out a deal with the White House to secure it, a claim the executive mansion rejected on Sunday.

Republicans have claimed that the vaccine mandate has hurt recruitment efforts, and has led to service members being removed from the US armed forces.