Congressional Republicans challenged Defense Secretary Leon Panetta on Tuesday to explain why the Defense Department allowed active-duty troops to wear their uniforms while marching in San Diego's gay pride parade last weekend.

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In a letter to Panetta, Sen. Jim Inhofe of Oklahoma said department rules bar service members from participating in political activities while in uniform and pressed Panetta on why a waiver was granted, who requested it and why it was considered over others.

Inhofe, who serves on the Armed Services Committee, also pointed out that administrative action has been taken against service members who have violated the rule.

"If the Navy can punish a chaplain for participating in a pro-life event or a Marine participating in a political rally, it stands to reason that the Defense Department should maintain the same standard and preclude service members in uniform from marching in a gay pride parade," Inhofe wrote.

In a statement accompanying the letter, Inhofe said he was concerned that the Obama administration "continues to force its liberal social agenda on the military by promoting the homosexual agenda, mandating the use of high-cost green energy initiatives, pursuing abortion rights and suppressing the free exercise of religious liberties."

Rep. Duncan Hunter of El Cajon said, "The Pentagon undermined its own policy on uniforms and parades by granting the waiver and I agree with the complaint lodged by other Republican committee members."

On Saturday, dozens of soldiers, sailors and Marines in uniform marched alongside an old Army truck with a "Freedom to Serve" banner and a rainbow flag. Dozens of military personnel in civilian clothes joined them.

Sean Sala, who is with the group ServiceMembers United, marched in the parade wearing his uniform. He served in the Navy.

"[It was] one of the most empowering experiences ever," he said. "I'll remember it for the rest of my life."

The Pentagon had advised all its branches that it was making an exception for the San Diego parade even though its policy prohibits service members from marching in uniform in political parades. The department said it made the exception because organizers had encouraged military personnel to march in their uniform and the event was getting national attention.

The waiver only applied to this year's parade in San Diego.

Rep. J. Randy Forbes, R-Va., a member of the House Armed Services Committee, issued a statement condemning the waiver.

"I am calling on the Defense Department to halt these dangerous exceptions to policy for political purposes," Forbes said. "This decision was an outrageous and blatantly political determination issued solely to advance this administration's social agenda."

The administration, with the backing of Congress, ended the policy barring gays to serve openly in the military. Nevertheless, several Republicans in Congress have been critical of the change in policy and have pushed legislation to limit the new policy.

Sala said that "don't ask, don't tell" is now a thing of the past.

"We are your sons, your daughters, fighting for your freedom and although the policy is gone, some people just don't get it," he said.