The head of the US Marines said on Thursday he opposed ending the ban on gays serving openly in the military, the first top officer to break openly with President Barack Obama over the issue.
General James Conway told the Senate Armed Services Committee that he disagreed with Obama's plan to repeal the ban.
"My best military advice to this committee, to the (defense) secretary, and to the president would be to keep the law such as it is."
Conway said the current policy worked and any bid to lift the ban should answer the question: "do we somehow enhance the war fighting capabilities of the United States Marine Corps by allowing homosexuals to openly serve?"
Conway's public rejection of his commander-in-chief's stance is sure to fuel debate in Congress on the issue and reflects apprehension among some senior military officers about changing the 1993 law.
The chiefs of the US Army and Air Force also expressed doubts about lifting the ban at congressional hearings this week, saying they were concerned about putting the military under further strain in the midst of two wars.
But Conway went further, making it clear he opposed lifting the ban that requires gay service members to keep quiet about their sexual orientation or face expulsion from the military.
His comments contrasted sharply with the chairman of the Joint Chiefs of Staff, Admiral Mike Mullen, who has spoken forcefully in favor of ending the ban.
Defense Secretary Robert Gates has called for a review of the issue to survey service members and examine the possible effect of changing the law, known as "Don't Ask, Don't Tell."
Senator Joe Lieberman disagreed with Conway, saying he believed the review would show that allowing gays to serve openly would bolster the military's battle readiness.
"This has to pass the test of military readiness. I believe it will based on my knowledge of what's happened in other militaries," he said, citing British and Canadian forces who serve alongside American troops in Afghanistan.