The Obama administration is saying little about new claims that U.S. diplomats in Libya made repeated requests for more security before the Sept. 11 attack in Benghazi that killed ambassador Christopher Stevens and three other Americans.

"I'm not going to get into a situation under review by the State Department and the FBI," said White House spokesman Jay Carney.

State Department spokesperson Victoria Nuland said Secretary of State Hillary Rodham Clinton will respond to a letter from two Republican House members citing requests for more security in the months ahead of the attack.

MORE: House committee: Requests for security in Libya denied

"We want to get to the bottom of precisely what happened and learn any lessons that we need to learn from it," Nuland said. "We're taking this very, very seriously."

The two House members -- Reps. Darrell Issa and Jason Chaffetz -- said in a letter to Clinton that information about previous security requests came from individuals with direct knowledge of events in Libya."

Issa and Chaffetz also made reference to the administration's changing views about the source of the attack, now generally attributed to terrorists that may include al Qaeda.

"It was clearly never, as administration officials once insisted, the result of a popular protest" over an anti-Islam film, wrote Issa and Chaffetz.

The lawmaker said they are planning an Oct. 10 hearing on the Benghazi attack.

Clinton addressed the issue last month: "Let me assure you that our security in Benghazi included a unit of host government security forces, as well as a local guard force of the kind that we rely on in many places around the world."

The Associated Press reported that the Issa/Chaffetz letter listed a dozen instance of questionable security in Benghazi before the Sept. 11 attack:

"-- Just weeks before the attacks, the unarmed Libyan guards at the consulate, employed by British contractor Blue Mountain Group, were warned by family members to quit their jobs because there were rumors of an impending attack.

-- In April, a gun battle erupted about two miles from the consulate between an unidentified armed group and forces loyal to the transitional government. Also in April, two Libyans fired from a contractor providing security at the consulate threw a small explosive device over the consulate fence. There were no casualties.

-- In June, a posting on a Facebook page mentioned Stevens' early morning runs around Tripoli along with members of his security detail. The page contained a threat against Stevens and a stock photo of him. Stevens stopped the runs for about a week, but then resumed.

-- Also in June, assailants placed an explosive device on a gate of the U.S. consulate, which blew a hole in the security perimeter. That month, there was a daylight attack on a two-car convoy carrying the British ambassador to Libya."

USA Today