WASHINGTON — President Obama vetoed a sweeping $612 billion defense policy bill Wednesday in a rebuke to congressional Republicans, and insisted they send him a better version that doesn’t tie his hands on some of his top priorities.

In an unusual veto ceremony, Obama praised the bill for ensuring the military stays funded and making improvements on military retirement and cybersecurity. Yet he pointedly accused Republicans of resorting to “gimmicks” and prohibiting other changes needed to address modern security threats.

“Unfortunately, it falls woefully short,” Obama said. “I’m going to be sending it back to Congress, and my message to them is very simple: Let’s do this right.”

The bill included more than $1 billion in additional spending for destroyers being built at Bath Iron Works, as well as changes to a federal program that could help lure more development to the former Brunswick Naval Air Station.

“This bill contains important policy provisions involving issues such as acquisition reform, sexual assault in the military, curbing the potential use of torture, and positive modifications to the military pension system,” said Sen. Angus King, I-Maine. “This veto puts those provisions at risk, creates uncertainty in the military, and could have economic repercussions on Maine’s defense industry and the hardworking people who support our country’s national security.”

The rare presidential veto marked the latest wrinkle in the fight between Obama and Republicans who control Congress over whether to increase federal spending – and how.

Four years after Congress passed and Obama signed into law strict, across-the-board spending limits, both parties are eager to bust through the caps for defense spending. But Obama has insisted that spending on domestic programs be raised at the same time, setting off a budget clash with Republicans that has yet to be resolved.

“It’s very disturbing that President Obama put politics before bipartisan policy that would have helped our troops, their families, bolstered our national security and created jobs in Maine,” said Rep. Bruce Poliquin, a Republican from Maine’s 2nd District.

And, Sen. Susan Collins, R-Maine, said, “I am alarmed that this annual legislation has been vetoed by the president.”

“The veto sends the wrong message to both our allies and adversaries across the world at a time of tremendous instability and growing threats,” Collins added.

To side step the budget caps, lawmakers added an extra $38.3 billion to a separate account for wartime operations that is immune to the spending limits. The White House dismissed that approach as a “gimmick” that fails to deal with the broader problem or provide long-term budget certainty for the Pentagon.

Obama also rejects the bill as written due to provisions making it harder for him to transfer suspected terror detainees out of the military prison in Guantanamo Bay, Cuba, a key campaign promise. The White House also has expressed concerns over provisions preventing military base closures and funding equipment beyond what the military says it needs.

But Republicans lambasted Obama for prioritizing the domestic spending he seeks over the security of U.S. troops and the nation they protect.

The veto forces Congress to revise the bill or try to settle the larger budget dispute.