— WASHINGTON (AP) — Chuck Hagel faced his first major hurdle in his bid to become the nation's defense secretary as a bitterly divided Senate Armed Services Committee pushed toward a vote Tuesday on his nomination.

"We need a secretary of defense," Chairman Carl Levin, D-Mich., told Republicans who continued to press for a delay in the vote.

The session exposed the deep split on the panel as Republicans assailed President Barack Obama's selection and Democrats highlighted Hagel's military service.

Obama tapped Hagel, a 66-year-old former Republican senator from Nebraska and twice-wounded Vietnam War combat veteran, to succeed Defense Secretary Leon Panetta, who is stepping down after four years as CIA director and Pentagon chief.

Senate Majority Leader Harry Reid, D-Nev., is pressing for a full Senate vote later this week, most likely on Thursday.

Hagel faces fierce opposition from Republicans who have challenged his past statements and votes on Israel, Iran, Iraq and nuclear weapons. Sen. John McCain, R-Ariz., who was a close friend of Hagel's but split over the Iraq war and politics, said he would vote against the nomination.

McCain cited Hagel's opposition to an increase in U.S. forces in Iraq that McCain backed in 2007, as well as Hagel's halting performance at his confirmation hearing. McCain said the testimony "was the worst I've seen by any nominee before this committee."

Sen. Lindsey Graham, R-S.C., insisted that the former GOP senator was out of the mainstream. "He's in a league of his own," Graham said.

Democrats argued that the president should have deference in assembling his Cabinet and specifically his second-term national security team.

Some Democrats sought to offer explanations for Hagel's lackluster testimony during more than eight hours of testimony last month.

Sen. Jeanne Shaheen, D-N.H., said she certainly would have liked him to be feistier, and Sen. Angus King, I-Maine, said he wished Hagel had been more forceful.

Committee Republicans forced a delay in the expected vote last week when they pressed Hagel for further data on his personal finances.

Levin said the GOP demands were beyond the scope of those traditionally asked of previous nominees, Republican and Democrat — a point echoed by McCain. Levin set a committee vote that will probably break along party lines — 14 Democrats for Hagel, 12 Republicans against their former colleague — just hours before Obama's State of the Union address to Congress.

If Hagel is approved in committee, as expected, he faces GOP delaying tactics in the full Senate, with the panel's ranking Republican, Sen. Jim Inhofe of Oklahoma, insisting that any confirmation be based on 60 votes rather than a majority of the Senate.

But that effort has divided Republicans, with several longtime members opposed to the unprecedented step of filibustering a president's Cabinet nominee for defense secretary.

Late Monday, McCain met privately with several committee Republicans and urged them not to filibuster the Hagel nomination, pointing out that the roles could be reversed someday with a Republican president and GOP-controlled Senate.

"I'm encouraging my colleagues if they want to vote against Sen. Hagel that's one thing and that's a principled stand," McCain told a group of reporters. "We do not want to filibuster. We have not filibustered a Cabinet appointee in the past and I believe that we should move forward with his nomination, bring it to the floor and vote up or down."

McCain has not said how he would vote on the nomination, but has indicated he was learning against confirmation.

All 55 Democrats are expected to back Hagel, and two Republicans — Sens. Thad Cochran of Mississippi and Mike Johanns of Nebraska — have said they will vote for the nominee. At least five Republicans, including McCain, have said they oppose a filibuster despite their reservations or opposition toward the nominee.

More than a dozen Republicans have said they will oppose their former colleague, and several others have indicated they are likely to vote no. Sen. Kelly Ayotte, R-N.H., a member of the Armed Services Committee, said Tuesday she would vote against the nominee, citing his performance at his confirmation hearing.

Hagel seemed ill-prepared under withering cross-examination from committee Republicans in nearly eight hours of testimony on Jan. 31. He was repeatedly pressed about past statements and votes on Israel, Iran and nuclear weapons, with GOP lawmakers suggesting he wasn't sufficiently supportive of Israel or anti-Iran.

In a memo, Republicans focused on the 2005 fight over President George W. Bush's nomination of John Bolton to be ambassador to the United Nations, and Democrats who tried to stop the nomination. The position is not Cabinet-level, however.

Faced with a Democratic filibuster, Bush circumvented the Senate and made Bolton a recess appointment.