The Pentagon's top brass admonished an Army general Thursday for publicly advocating in favor of “don't ask, don't tell,” the 1993 policy that bans gay troops from serving openly.

Defense Secretary Robert Gates told reporters that Lt. General Benjamin Mixon's comments on the policy were “inappropriate” for an active duty officer.

In a March 8 letter published in Stars and Stripes, the US military's independent news source, Mixon said he disagreed with conventional wisdom that a majority of Americans oppose the law.

“I suspect many servicemembers, their families, veterans and citizens are wondering what to do to stop this ill-advised repeal of a policy that has achieved a balance between a citizen's desire to serve and acceptable conduct,” Mixon wrote.

Mixon also urged people to speak up in favor of the policy that prescribes discharge for gay and lesbian servicemembers who do not remain celibate or closeted.

“Now is the time to write your elected officials and chain of command and express your views,” he said. “If those of us who are in favor of retaining the current policy do not speak up, there is no chance to retain the current policy.”

Admiral Michael Mullen, chairman of the Joint Chiefs of Staff, also admonished Mixon, adding that the Army was looking into the issue.

“I've spoken with General Casey specifically about this,” Mullen said. “And General Mixon specifically is – the issue is being addressed with him.”

Mullen added that in light of President Obama's “strategic intent” to repeal the law the letter was “not appropriate.”

“And in the end, if there is either policy direction that someone in uniform disagrees with … you know, the answer is not advocacy, it is in fact to vote with your feet,” Mullen said.

The rebuke comes on the same day the Pentagon unveiled stricter guidelines on the firing gay troops under the policy.