WASHINGTON — The U.S. military did not quickly intervene during the attack on the U.S. Consulate in Libya last month because military leaders did not have adequate intelligence information and felt they should not put American forces at risk, Defense Secretary Leon Panetta said Thursday.

In his most extensive comments to date on the unfolding controversy surrounding the attack in Benghazi, Panetta said U.S. forces were on heightened alert because of the anniversary of 9/11 and prepared to respond. But, he said, the attack happened over a few hours and was over before the U.S. had the chance to know what was really occurring.

“(The) basic principle is that you don’t deploy forces into harm’s way without knowing what’s going on; without having some real-time information about what’s taking place,” Panetta told Pentagon reporters. “And as a result of not having that kind of information, the commander who was on the ground in that area, Gen. Ham, Gen. Dempsey and I felt very strongly that we could not put forces at risk in that situation.”

Panetta was referring to Gen. Carter Ham, the head of U.S. Africa Command, and Gen. Martin Dempsey, chairman of the Joint Chiefs of Staff.

In a letter to President Barack Obama on Thursday, House Speaker John Boehner questioned whether the White House considered military options during or immediately after the attack, and he questioned what the president knew about the security threats in the country. He said that the national debate over the incident shows that Americans are concerned and frustrated about the administration’s response to the attack.

“Can you explain what options were presented to you or your staff, and why it appears assets were not allowed to be pre-positioned, let alone utilized? If these reports are accurate, the artificial constraint on the range of options at your disposal would be deeply troubling,” Boehner, R-Ohio, wrote.

U.S. Ambassador Chris Stevens and three other Americans were killed in the attack, which has become a heated campaign issue less than two weeks before the election. Republicans have criticized the Obama administration’s failure to more quickly acknowledge that intelligence suggested very early on that it was a planned terrorist attack, rather than spontaneous violence erupting out of protests over an anti-Muslim film.