In a breakthrough in the effort to overhaul the military's "don't ask, don't tell" policy, Congress is set to vote as early as this week on a proposal to repeal the rule barring gays from serving openly in the military.
But the Obama administration nevertheless backed the plan, saying the proposed amendment would still allow the Department of Defense to finish its work before implementing any changes.
Rep. Patrick Murphy, D-Pa., plans to offer an amendment to the annual defense spending blueprint bill known as the defense authorization later this week.
In the Senate, the measure will be debated and voted on in the Armed Services Committee later this week in closed session.
The move to accelerate a vote on the matter drew an impassioned and split reaction from lawmakers and advocacy groups.
Elaine Donnelly, president of the Center for Military Readiness, called the proposal a "high-handed White House ploy" that defies the advice from top defense officials who wanted to wait until the Pentagon finishes its review.
Rep. Mike Pence, R-Ind., called the planned vote "premature." House Armed Services Committee Chairman Ike Skelton, D-Mo., who is facing a tough reelection battle at home, said he opposes the repeal, though he would not say whether he would vote against it. Rep. Buck McKeon, R-Calif., ranking Republican on that committee, said he would vote against it.
On the Senate side, most committee Republicans are expected to oppose the measure, including war veteran Sen. John McCain, R-Ariz.
Democrats have a 14-12 majority on the committee. Sen. Ben Nelson, D-Neb., has said he does not support repeal, but a spokesman for Sen. Susan Collins, R-Maine, told Fox News she would probably support the efforts of Sen. Joe Lieberman, I-Conn., to push for the measure.
The vote is expected to be close and could come down to the vote of the Senate's newest member, Sen. Scott Brown, R-Mass., who has said he wants to consult with the generals before making any decision.
Gay advocacy groups lauded the breakthrough.
"We are on the brink of historic action to both strengthen our military and respect the service of lesbian and gay troops," Human Rights Campaign President Joe Solmonese said in a written statement. "Without a repeal vote by Congress this year, the Pentagon's hands are tied."
White House Budget Director Peter Orszag said in a letter to Lieberman that while the White House would "ideally" like the Pentagon to first complete its review, the proposal will "ensure that the implementation of the repeal is consistent with standards of military readiness, effectiveness, unit cohesion, recruiting and retention."
Adm. Mike Mullen, chairman of the Joint Chiefs of Staff, supports repeal, though some generals have indicated opposition.
Defense Secretary Robert Gates also backs overhauling the policy, though the Pentagon issued a statement Tuesday that he'll accept Congress' plan to accelerate the timeline.
"Secretary Gates continues to believe that ideally the (Department of Defense) review should be completed before there is any legislation to repeal the don't ask don't tell law. With Congress having indicated that is not possible the secretary can accept the language in the proposed amendment," reads a statement from Pentagon Press Secretary Geoff Morrell.
Fox News' Trish Turner and Justin Fishel contributed to this report.