Richmond, Virginia (CNN) - Mitt Romney accused Vice President Joe Biden of "doubling down on denial" as details continued to trickle out about the Benghazi attacks that killed four Americans last month.
It was the second time in as many days that Romney sharply criticized the Obama administration for its posture in the aftermath of the attack.
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At an outdoor rally in Richmond, Romney said Biden had raised more questions about the administration's handling of the deadly incident when he "directly contradicted the testimony of State Department officials," during the vice presidential debate Thursday night.
"He's doubling down on denial. And we need to understand exactly what happened as opposed to just having people brush this aside," Romney said. "When the vice president of the United States directly contradicts the testimony, sworn testimony, of state department officials, American citizens have a right to know just what's going on."
On Thursday night, Biden told the debate moderator "we did not know" about requests for more security in the months before the attack on the United States' consulate in Benghazi.
"We weren't told they wanted more security there," Biden said when pressed during the debate. "We did not know they wanted more security again."
Republicans pounced, citing congressional testimony from State Department officials about requests for more security staffing in Libya.
On Friday White House spokesman Jay Carney clarified Biden's comments, saying the vice president had been referring to himself, the president and the White House, not the broader administration.
Carney said the requests for additional security in Libya had been handled by the State Department and had not reached the White House.
Romney had criticized the president a day earlier, after Obama's deputy campaign manager accused the Republican ticket of trying to politicize the Libya attacks.
"It's an issue because this is the first time in 33 years that a United States ambassador has been assassinated," Romney said. "Mr. President, this is an issue because we were attacked successfully by terrorists on the anniversary of 9/11. President Obama, this is an issue because Americans wonder why it was it took so long for you and your administration to admit that this was a terrorist attack."
"This is a very serious issue," Romney continued. "These are very serious questions, and the American people deserve serious answers and I hope they come soon."