Defense Secretary Robert Gates on Tuesday announced he is appointing a task force to study how the military would implement a repeal of the controversial "don't ask, don't tell" policy that bars gays from serving in the military.

The announcement was made during a hearing of the Senate Armed Services Committee. It comes less than a week after President Obama told Congress he plans to work with lawmakers and senior defense and military officials this year to repeal the 1993 law, which has resulted in the discharge of an estimated 13,500 service personnel.

Gates has tapped Pentagon General Counsel Jeh Johnson and Gen. Carter Ham, commander of U.S. Army Europe, to lead the working group and report their findings by the end of the year.

The group's guiding principle, Gates said, is to minimize disruption in the ranks, with special attention paid to deployed troops. They will study a range of issues, including any changes to benefits, base housing and personnel policies that would be made necessary by repealing the law.

Meanwhile, the Pentagon is conducting a 45-day review to determine how to implement the current law in a "more humane and fairer manner," Gates said.

"We believe that we have a degree of latitude within the existing law to change our internal procedures in a manner that is more appropriate and fair to our men and women in uniform," Gates said.

Senate Armed Services Committee Chairman Carl Levin, D-Mich., who strongly supports allowing gay men and women to serve in the military, told reporters that the fiscal 2011 defense authorization bill could carry a moratorium on enforcing the 1993 law to allow the Defense Department more time to study the issue.

"It's a question of what's achievable," he said, adding that he would prefer a repeal.

Several Republicans on the panel argued that changing the law, particularly during a time of war, is unnecessary and could harm unit cohesion.

"Has this policy been ideal? No, it has not," said Armed Services Committee ranking member John McCain, R-Ariz. "But it has been effective. It has helped to balance a potentially disruptive tension between the desires of a minority and the broader interests of our all-volunteer force."

The 1993 law is itself a compromise forged by the Joint Chiefs of Staff and then-President Bill Clinton, who had promised repeatedly during his campaign for the White House to end the expulsion of gays in the military. Under that law, military commanders cannot ask about a person's sexual orientation and military personnel must keep their homosexuality hidden.

During the 90-minute hearing, Joint Chiefs of Staff Chairman Michael Mullen said the military must proceed carefully and address any issues that could be disruptive to the force. But the admiral said allowing gays to serve openly in the military is the "right thing to do."

"To me, personally, it comes down to integrity - theirs as individuals, and ours as an institution," he said.