WASHINGTON – Sen. Lisa Murkowski announced Thursday that she will vote against confirming Pete Hegseth to lead Pentagon, becoming the first Republican to oppose one of President Donald Trump’s Cabinet picks.

The Alaska Republican’s decision comes ahead of a crucial test vote to advance Hegseth’s nomination toward confirmation.

THIS IS A BREAKING NEWS UPDATE. AP’s earlier story follows below.

WASHINGTON (AP) —

Senate GOP leaders rushed to advance Pete Hegseth as President Donald Trump’s defense secretary nominee in a crucial test vote Thursday, despite grave objections from Democrats and stirring unease among Republicans over his behavior and qualifications to lead the U.S. military.

Rarely has a Cabinet choice encountered such swirling allegations of wrongdoing, including excessive drinking and aggressive actions toward women, which he has largely denied. Trump is standing by Hegseth, and the chairman of the Senate Armed Services Committee has dismissed the claims as factually inaccurate.

“I am ironclad in my assessment that the nominee, Mr. Hegseth, is prepared to be the next secretary of defense,” the chairman, Sen. Roger Wicker, R-Miss., said in a statement on the eve of the test vote. “The Senate needs to confirm this nominee as fast as possible.”

A new president’s national security nominees are often the first to be lined up for confirmation, to unsure U.S. safety at home and abroad. Already the Senate has overwhelmingly confirmed Marco Rubio as secretary of state in a unanimous vote, and it was on track to confirm John Ratcliffe as CIA director later Thursday.

But Hegseth stands in a category of his own amid allegations that he sexually assaulted a woman at a Republican conference in California, which he has denied as a consensual encounter, and of heavy drinking at events when he led a veterans organization. He has also said women should not work in combat roles, a view he has since tempered during his confirmation process.

A new claim emerged this week in an affidavit from a former sister-in-law who claimed Hegseth was abusive to his second wife to the point that she feared for her safety. Hegseth has denied the allegation. In divorce proceedings, neither Hegseth nor the woman claimed to be a victim of domestic abuse.

Senate Democratic Leader Chuck Schumer said Thursday that Hegseth is unqualified for the job because of his personal behavior, including drinking, and his lack of experience.

“One of the kindest words that might be used to describe Mr. Hegseth is erratic, and that’s a term you don’t want at DOD,” Schumer said. “He has a clear problem of judgment.”

A Princeton and Harvard-educated former combat veteran, Hegseth went on to make a career at Fox News, where he hosted a weekend show. Trump tapped him as the defense secretary to lead an organization with nearly 2.1 million service members, about 780,000 civilians and a budget of $850 billion.

Hegseth has promised not to drink on the job if confirmed.

But senators have remained doubtful of his experience and abilities and the alleged behavior that could lead to reprimand or firing for military personnel he would now be expected to lead.

It will take a simple majority of 50 senators to advance Hegseth’s confirmation in Thursday’s vote. Most Republicans, who hold a 53-seat majority in the chamber, have signaled they will back the nominee, including Sen. Joni Ernst, R-Iowa, herself a combat veteran and sexual assault survivor.

However, several GOP senators, including Sen. Lisa Murkowski of Alaska and Sen. Susan Collins of Maine, are being widely watched for their votes.

Vice President JD Vance could be called upon to break a tie vote to advance Hegseth toward confirmation.

During a fiery confirmation hearing, Hegseth swatted away allegations of wrongdoing one by one — dismissing them as “smears” — as he displayed his military credentials and vowed to bring “warrior culture” to the top Pentagon post.

Wicker said he had been briefed a third time on the FBI background investigation into Hegseth. He said “the allegations unfairly impugning his character do not pass scrutiny.”