Signaling the growing seriousness of the Obama administration's commitment this year to ending the military's ban on gays serving openly in the armed forces, the Defense Department said Sunday that it will release a long-awaited report on the matter earlier than planned because senators are eager to vote on whether to repeal the policy.

Defense Secretary Robert M. Gates has ordered the report to be released Nov. 30, one day earlier than planned, "to support Congress's wish to consider repeal before they adjourn," Pentagon spokesman Geoff Morrell said Sunday.

The Senate is slated to vote again on a defense policy bill that includes language that would repeal the "don't ask, don't tell" policy after the Thanksgiving recess. The measure did not advance in September. Several senators asked Gates last week to release the report early so the Senate Armed Services Committee could hold hearings on it before the full Senate votes. Several moderate senators have said they will not decide how to vote until they read the report.

Gates "has instructed his staff, without cutting any corners, to have everything ready a day sooner because he wants to ensure members of the Armed Services Committee are able to read and consider the complex, lengthy report before holding hearings with its authors and the Joint Chiefs of Staff," Morrell said in a statement.

Gates; Adm. Mike Mullen, the chairman of the Joint Chiefs of Staff; and the report's co-chairmen, Army Gen. Carter Ham and Pentagon General Counsel Jeh Johnson, could testify before the committee, aides said.

The report is expected to conclude that the military can lift the ban on gays serving openly in uniform with only minimal and isolated incidents of risk to the current war efforts, according to sources who shared details of the report with The Washington Post.

The report will cite a survey of active-duty and reserve troops that found that more than 70 percent of respondents said the effect of lifting the ban would be positive, mixed or nonexistent, sources said.

About 40 percent of the Marine Corps is concerned about lifting the ban, one of the sources said. Mullen said Sunday that he is confident that Gen. James Amos, the Marine Corps commandant, will be able to carry out orders to end the ban if Congress votes to do so, despite his public comments of concern.