WASHINGTON — Accusing Republicans of a new level of obstruction, Senate Democrats moved on Wednesday to force a vote on President Obama’s nomination of Chuck Hagel to be secretary of defense.

Mr. Hagel’s nomination was endorsed by the Senate Armed Services Committee along party lines on Tuesday. But with Republicans demanding more information before allowing a vote on Mr. Hagel by the full Senate, Senator Harry Reid of Nevada, the majority leader, took procedural steps to limit floor debate on his nomination and bring the partisan clash to a head by Saturday.

“This is the first time in the history of our country that a presidential nominee for secretary of defense has been filibustered,” Mr. Reid said on the Senate floor. “What a shame. But that’s the way it is.”

Republicans, sensitive to the accusation that they were filibustering Mr. Hagel, tried to draw a distinction between a filibuster and delaying the vote because of unanswered questions.