WASHINGTON (AP) - Struggling to break an impasse, Senate Democrats set a test vote Thursday on whether to advance Chuck Hagel's nomination as defense secretary after Republicans blocked speedy confirmation of their former colleague and Vietnam combat veteran. Hours of behind-the-scenes talks yielded the decision by Senate Majority Leader Harry Reid, but no clear sign of whether President Barack Obama's nominee would receive the 60 votes required to move the Senate to a final vote on whether to confirm him. Democratic officials said the vote was scheduled with only a handful of votes needed to clear the threshold. Sen. John McCain of Arizona led the opposition to Hagel's confirmation, but he said he would not object to the test vote, called cloture. The remaining "yes" votes remain elusive, even after the White House responded to McCain's demand for information unrelated to Hagel. McCain and Sens. Lindsey Graham of South Carolina and Kelly Ayotte of New Hampshire said they would delay the vote until they got a more detailed accounting of Obama's actions on the night of the attack on the U.S. diplomatic mission in Benghazi, Libya, where Ambassador Chris Stevens and three other Americans were killed. Republicans have sought to portray Obama as being out of touch during the raid and demanded to know whether Obama spoke to any Libyan official during the Sept. 11 assault. The Republicans' demand has had the effect of a filibuster. The White House responded Thursday by saying former Secretary of State Hillary Clinton called Libyan President Mohamed Magariaf on Obama's behalf on Sept. 11 to coordinate additional support to protect Americans in Libya, White House counsel Kathryn Ruemmler wrote the senators. Obama spoke to Magariaf on the evening of Sept. 12, she said. The Obama administration also had disclosed the calls at the time they were made. A White House official said Thursday that if there had been a need to push the Libyans to do something, Obama would have called, but the official said the Libyans were trying to do the right thing and were being as helpful as possible. Moreover, the official, discussing internal communications only on the condition of anonymity, said the earlier call with Clinton had gone well. Reid said it was "shocking" and "tragic" that the GOP would attempt to block Hagel's nomination at a time when the U.S. military is engaged in so many places around the world. "Not a single nominee for secretary of defense ever in the history of our country has been filibustered," he said in a speech on the Senate floor. Reid said Republicans notified him Wednesday night they would withhold the votes needed to advance Hagel's nomination. Reid said he considered that a "full-scale filibuster" because the Republican strategy would prevent Hagel's nomination from getting the required 60 votes. Republicans are seeking "extraneous requests" for information that will never be satisfied, Reid said. "The pattern has been clear for months: as soon as President Obama's administration responds to one request, Republicans devise another, more outlandish request," Reid said. A full Senate vote on Hagel, a former two-term Republican senator from Nebraska and twice-wounded Vietnam veteran, was expected to be held Friday after Reid filed a motion to limit debate. While Democrats hold a 55-45 edge in the Senate and have the numbers to confirm Hagel on a majority vote, they need the support of five Republicans to clear the way for a majority vote. A third, Sen. Susan Collins of Maine, has said she will vote against Hagel's confirmation, but would not join in a filibuster to block a final vote. Graham said Wednesday that he would vote against ending debate on Hagel's nomination. McCain declined to say whether he would try to delay Hagel's confirmation if Obama did not provide an answer. The nomination of John Brennan as CIA director is also being delayed; the Senate Intelligence Committee is pushing off a vote amid demands that the White House turn over more details about drone strikes against terror suspects and about the Benghazi attacks. Intelligence Committee Chairwoman Dianne Feinstein of California said a vote likely will be postponed till late February. The committee's Republicans were unified in opposition to their onetime colleague, who will succeed Defense Secretary Leon Panetta if he's confirmed. Obama "stands strongly" behind Hagel and believes he "will do a wonderful job," White House spokesman Josh Earnest said aboard Air Force One en route to Decatur, Ga., where the president traveled Thursday to speak about early childhood education. If confirmed by the Senate, Hagel, 66, would take charge of the U.S. armed forces at a time of turmoil. Automatic cuts to the Pentagon's budget are looming, American troops in Afghanistan are being halved over the next year, North Korea has tested a nuclear weapon, Iran remains a threat in the Persian Gulf region, and Syria, Iraq, Libya, Egypt, Mali and Tunisia all are in a state of unrest. At a Pentagon award ceremony on Thursday for former Secretary of State Hillary Rodham Clinton, Panetta said it was fitting to recognize her accomplishments on Valentine's Day. And he said the second-best Valentine's Day present would be for the Senate to confirm Hagel and allow Panetta and his wife to "get the hell out of town." He said he's got his belongings packed. Hagel has faced intense opposition from Republicans, who have challenged his past statements and votes on Israel, Iran, Iraq and nuclear weapons. Associated Press writers Alan Fram, Donna Cassata and Jim Kuhnhenn contributed to this report.