LIMA (Reuters) - U.S. Secretary of State Hillary Rodham Clinton assumed responsibility on Monday for last month's deadly attack on the U.S. diplomatic mission in Benghazi, Libya, which has become an issue in the hard-fought U.S. presidential campaign.

"I take responsibility" for what happened on September 11, Clinton said in an interview with CNN during a visit to Peru, adding that President Barack Obama and Vice President Joe Biden would not be responsible for specific security instructions for U.S. diplomatic facilities.

"I'm in charge of the State Department's 60,000-plus people all over the world," Clinton said.

"The president and the vice president wouldn't be knowledgeable about specific decisions that are made by security professionals. They're the ones who weigh all of the threats and the risks and the needs and make a considered decision."

Clinton's comments followed stepped-up criticism of the Obama administration over the Benghazi attack, which Republican presidential challenger Mitt Romney has sought to use to dent Obama's foreign policy credibility before the November 6 election.

Republicans in particular have focused on the Obama administration's shifting explanations for the attack, which Clinton said in two separate television interviews on Monday were the result of "the fog of war."

"Remember, this was an attack that went on for hours," Clinton told Fox News. "There had to be a lot of sorting out. ... Everyone said, here's what we know, subject to change."

The administration initially attributed the violence to protests over an anti-Islam film and said it was not premeditated. Obama and other officials have since said the incident was a terrorist attack.

"POLITICAL GOTCHA"

The Benghazi assault, and the Obama administration's response, has become a contentious election issue and Clinton's comments came a day before the second presidential debate.

"What I want to avoid is some kind of political 'gotcha' or blame game going on," Clinton told CNN.

"I know that we're very close to an election. I want to just take a step back here and say from my own experience, we are at our best as Americans when we pull together. I've done that with Democratic presidents and Republican presidents."

Romney has accused the administration of not providing adequate security to American diplomats and misrepresenting the nature of the attack, which resulted in the death of U.S. Ambassador Christopher Stevens and three other Americans.

Romney's criticisms have sought to undercut the foreign policy record of Obama, who has been praised for the killing of al Qaeda leader Osama bin Laden and the withdrawal of troops from unpopular wars in Iraq and Afghanistan.

Those attacks sharpened after last week's vice presidential debate, when Vice President Joe Biden said "we did not know" of requests by U.S. diplomats on the ground in Libya for more security - a statement that contradicted testimony given two days earlier by State Department officials at a congressional hearing.

Clinton told the networks that Obama and Biden had not been involved in security decisions related to the consulate.

"The decisions about security are made by security professionals. But we're going to review everything to be sure we're doing what needs to be done in an increasingly risky environment," Clinton said.

Congress has increased pressure on the State Department to release information about the attack. Obama and Clinton have both vowed a full investigation.