By CNN Foreign Affairs Reporter Elise Labott

The Libyan government will not allow the FBI into Benghazi to arrest suspects for last year's deadly terror attack on the U.S. diplomatic mission, a top State Department official told a House panel on Wednesday.

Federal authorities have filed charges against suspects in connection with the September 11 attack on the mission and nearby CIA annex that killed Ambassador Christopher Stevens and three other Americans.

But Republicans on the House Foreign Affairs Committee said they were shocked nobody has been brought to justice.

"Not one terrorist perpetrator has been captured or killed, despite the president saying that this was his highest priority," said Rep. Ed Royce, the panel's Republican chairman.

Rep. Ted Poe added that CNN's Arwa Damon interviewed Ahmed Khattalah in broad daylight. Khattalah is the leader of a Libyan militia officials believe was involved in the assault and has been charged by federal prosecutors.

"After a year, we can't find these people but yet a CNN reporter can go to Benghazi at a hotel, at a coffee shop and have coffee with the suspected ringleader of (of this group) indicted by our government," Poe said. "Maybe the FBI ought to just ask the CNN reporter `how did you get a hold of this guy?'"

Undersecretary for Management Patrick Kennedy told the committee the security situation is too dangerous for U.S. authorities to enter Benghazi. While he said the United States was "working with the Libyan government," he did not offer specifics.

"Benghazi has taken, even since the events of 9/11, a serious turn for the worse. Yes, they will let journalists in, but they are not letting U.S. law enforcement in to arrest people there because the government of Libya is not in control to that degree," Kennedy said.

Kennedy also faced criticism from House Republicans that the State Department did not hold senior agency officials accountable for security shortcomings ahead of the attack.

"No State Department personnel have been fired or even disciplined," said Rep. Ed Royce. "No one has missed a paycheck."

The hearing was the first of three this week scheduled by House Republican leadership as part of its ongoing investigation into the Obama administration's conduct leading up to, during and following the attack.

Republicans have said the State Department ignored requests for additional security and scapegoated midlevel officials to protect the leadership of the department, including then-Secretary of State Hillary Clinton.

Four State Department employees were removed from their posts and placed on administrative leave last December following an independent review of the attack. Secretary of State John Kerry last month reinstated the officials to new jobs, which State Department officials said have less responsibility.

Kennedy told the committee that reassigning the employees amounted to "serious accountability," although Rep. Ileana Ros-Lehtinen, a Republican, said the State Department did little more than "shuffle the deck chairs."

An independent panel on the Benghazi attack blamed the State Department's diplomatic security bureau, which is overseen by Kennedy, for failing to implement adequate security at the Benghazi post.

The Accountability Review Board, led by former Ambassador Thomas Pickering, made 29 recommendations, one of which was another independent review to identify "best practices" in the public and private sectors in security intelligence, risk management and accountability, all areas where problems were identified at the State Department.

That panel, led by former Secret Service Director Mark Sullivan, warned that the State Department did not pay enough attention to the bureau overseeing security for 275 diplomatic posts and called for it to be elevated in its importance to deal with a growing threat.

As a result of the Benghazi attack, the State Department created a new position of deputy assistant secretary of state for high threat posts and has begun to beef up security and improve training.

But the Sullivan panel's report found those steps to be inadequate without establishing clear lines of authority and responsibility for diplomatic security were lacking. A new undersecretary, the report said, would be responsible for "conducting threat and vulnerability assessments to identify risk" and recommending safeguards. Kennedy said on Wednesday that the undersecretary job was being examined.

"We will do everything we can to deter and mitigate the effectiveness of any attack, but we will not, even with willing and capable governments as our partners stop terrorists or extremists from mounting attacks against us in all cases," Mr. Kennedy said, adding that global diplomacy was an inherently dangerous job.

On Thursday, Pickering and former Joint Chiefs Chairman, Adm. Mike Mullen, who was also on the Accountability Review Board, will testify before the House Oversight and Government Reform Committee, as will Mark Sullivan.

The House Armed Services Committee panel will also meet Thursday to examine the military's preparedness to respond to terrorist attacks like the one in Benghazi.