Updated

MELBOURNE, Australia -- The top U.S. military officer said Monday he was startled by a public panning of the proposal to lift the military's ban on gays from the head of the Marine Corps.

Adm. Mike Mullen, chairman of the Joint Chiefs of Staff, said he thought the top brass had agreed to make recommendations privately to Defense Secretary Robert Gates.

Marine Corps Commandant Gen. James Amos had said that with forces fighting in Afghanistan and still deployed in Iraq, now is the wrong time to lift the ban.

"This is not a social thing. This is combat effectiveness," Amos said Saturday.

President Barack Obama has promised to repeal the ban known as "don't ask, don't tell," which was installed by Congress in 1993. Mullen supports changing the law after a period of study and planning.

"I was surprised by what he said and surprised he said it publicly," Mullen told reporters in Australia, where he attended meetings of defense and diplomatic chiefs.

He said the heads of the military services had committed to "look at the data and then make our recommendations privately."

That amounted to a mild rebuke of Amos, but Mullen said he had not spoken to Amos about the remarks.

A Pentagon study of the effects of repeal is due Dec. 1.

The Marine Corps has long been the military branch most worried that lifting the ban would hurt the ability to fight and harm the tight personal bonds within military units.

"There is nothing more intimate than young men and young women -- and when you talk of infantry, we're talking our young men -- laying out, sleeping alongside of one another and sharing death, fear and loss of brothers," Amos said Saturday. "I don't know what the effect of that will be on cohesion. I mean, that's what we're looking at. It's unit cohesion, it's combat effectiveness."

The House has passed legislation repealing "don't ask, don't tell," but it has not yet seen a vote in the full Senate, where Democrats don't have the votes to overcome a Republican filibuster. Democratic leaders says they are trying to reach a deal in the Senate.