The White House says President Barack Obama will veto a sweeping $612 billion defense policy bill, citing objections over how the measure is funded.
Obama will veto the National Defense Authorization Act for fiscal year 2016 Thursday afternoon in the Oval Office.
The president also disapproves of provisions in the bill that would complicate his pledge to close the U.S. detention facility at Guantanamo Bay, Cuba.
It's the first time Obama has rejected the measure. Presidents have signed the bipartisan bill into law annually for more than 50 years.
The move will force Congress to revise the bill or try to settle a larger budget dispute that led Obama to veto it.
House Speaker John Boehner noted that the annual bill is one of the few bipartisan measures in Congress that has readily become law 53 consecutive years. He urged Obama to pick a different way to make his point in the standoff over whether Congress should break through spending caps when it comes to defense, but adhere to them for domestic agencies.
Obama and his Democratic supporters say no. Republicans argue that the bill authorizes money for national security amid global threats.
Senate Majority Leader Mitch McConnell said he was "stunned" at Obama's veto threat and said there were enough votes in the Senate to override it. Both the House and Senate would have to override the veto, but if the House sustains Obama's veto, the Senate would not even vote.
The bill would increase defense spending by adding $38 billion to a separate war-fighting account. The White House says that's a "funding gimmick."