AP Photo/Steve Helber

RICHMOND, Va. — Mitt Romney criticized Vice President Biden on Friday for "directly contradicting the sworn testimony of State Department officials" during Thursday night's vice-presidential debate, picking up on GOP attacks leveled at Biden in the hours since the exchange.

"He’s doubling down on denial, and we need to understand exactly what happened as opposed to just having people brush this aside," Romney told a crowd gathered outside an auto dealership in Richmond. "When the vice president of the United States directly contradicts the sworn testimony of State Department officials, American citizens have the right to know just what’s going on."

Biden said that "we" were unaware of security concerns in Libya. White House officials clarified Friday that the vice president was speaking for himself and President Obama. State Department officials, they said, had not passed on requests for more security. 

Speaking Friday at the Center for Strategic and International Studies in Washington, Secretary of State Hillary Rodham Clinton avoided specifics about the Benghazi post's security but broadly defended the need to station U.S. diplomats in dangerous places to support the Arab world's emerging democracies.

Vowing that "we will not retreat," she said the United States "will never prevent every act of violence or terrorism, or achieve perfect security." She added: "Our people can't live in bunkers and do their jobs. But it is our solemn responsibility to constantly improve, to reduce the risks our people face and make sure they have the resources they need."

Clinton noted that "diplomacy, by its very nature, is often practiced in dangerous places." Supporting democratic transitions is "not a matter of idealism" for the United States but "a strategic necessity," she told the think tank audience. "We will not pull back our support for emerging democracies when the going gets tough. That would be a costly strategic mistake that would undermine both our interests and our values."

Romney credited his running mate, Rep. Paul Ryan (R-Wis.), for his debate performance, calling the lawmaker "thoughtful, respectful, steady, poised, the kind of person you want to turn to in a crisis."

Referring to Biden later, Romney said: "The other candidate of course just attacked. The American people are looking for answers, not attacks."

Romney's decision to zero in on Biden's comments regarding the attack last month on a U.S. diplomatic post in Benghazi guarantees that Republicans will continue attempting to chip away at the Obama administration's foreign policy record in the closing weeks of the campaign.

Making the argument in Virginia — a state with a significant military population — could help Romney close the gap here as the race appears to be tightening. It is the second time this week that the GOP nominee has discussed foreign policy in the state, after giving a speech on his foreign policy agenda Monday at the Virginia Military Institute.

The Republican ticket holds a one-point lead over the president in Virginia in a poll released this week by NBC News and Marist College, while Obama holds a five-point edge over Romney in a poll published by CBS News, the New York Times and Quinnipiac University.

Romney arrived in Richmond on Friday with his senior aides and Sen. Rob Portman (R-Ohio), who has served as a stand-in for Obama during debate rehearsals. Romney watched the vice-presidential debate with Portman and senior campaign aides Thursday night at a mountainside resort in Asheville, N.C. after meeting Rev. Billy Graham for the first time and receiving an endorsement from the evangelical leader.

After his Virginia stop, Romney is scheduled to return to Ohio, where he has spent most of this week, for a dinnertime rally with Ryan. He will make three more stops across Ohio on  Saturday before taking a day off Sunday at his Massachusetts home.