Republican senators on Friday put pressure on President Obama to confirm his whereabouts during the night of the Benghazi attack, after an ex-White House spokesman revived the debate by telling Fox News he was not in the Situation Room.

The detail about the president's location the night of the attack is just one of many revelations that have, in a matter of days, kicked up the controversy to a level not seen since last year. After new emails were released raising questions about the White House response to the attack, a key panel on Friday subpoenaed Secretary of State John Kerry and House Speaker John Boehner announced a special investigative committee.

On Friday afternoon, three GOP senators wrote a letter to Obama asking about his whereabouts and spokesman Tommy Vietor's comments to Fox News.

"Last night, the former Communications Director for the National Security Council, Tommy Vietor, stated that on the afternoon and night of September 11, 2012 -- while the U.S. mission in Benghazi, Libya was under attack -- that you never visited the White House Situation Room to monitor events," they wrote.

Claiming that Americans still do not have an "accounting of your activities during the attack," the senators asked him to confirm Vietor's account. The letter was signed by Sens. John McCain, R-Ariz.; Lindsey Graham, R-S.C.; and Kelly Ayotte, R-N.H.

In the earlier interview with Fox News, Vietor said he was in the Situation Room during the Benghazi attack -- where four Americans including the U.S. ambassador died -- but Obama was not.

He said Obama was in the White House.

"It is well known that when the attack was first briefed to him it was in the Oval Office and he was updated constantly," Vietor said Thursday, adding he did not know where the president was at all points in the night because he does not have a "tracking device on him." He said Obama does not have to be in the Situation Room to monitor an ongoing situation.

Though officials have described the president as being in the loop that night, Republicans have questioned those claims. The matter was last debated during congressional testimony in February 2013.

At a hearing, top Defense officials said they had just one conversation with Obama during the course of the attack.

Then-Defense Secretary Leon Panetta and Joint Chiefs Chairman Gen. Martin Dempsey said they spoke with Obama at 5 p.m. ET on Sept. 11 that night. They were both on the same call, and said it lasted about 30 minutes.

Dempsey said they did not speak again until the attack was over.

Graham, at the time, said Obama "has to account for his leadership" and questioned whether Obama showed "any curiosity" as the attack unfolded.

Panetta said there was "no question" Obama "was concerned about American lives," and he assumed the chief of staff was keeping him updated.

The new letter questioning the president on his whereabouts marks just one front in Republicans' revived effort to get answers on the 2012 attack.

The decision by Boehner to call a vote on forming a select committee was a significant development, as Boehner for months has resisted calls by rank-and-file lawmakers to do so.

The new emails apparently pushed him to change his mind.

The emails in question were obtained and published by the conservative watchdog group Judicial Watch, following a Freedom of Information Act lawsuit. One email showed White House adviser Ben Rhodes discussing a "prep call" with then-U.N. ambassador Susan Rice, before she went on several Sunday shows and made controversial and flawed statements linking the attack to an anti-Islam Internet video

Top Republicans said those emails should have been turned over to Congress months ago.

But Senate Democratic Leader Harry Reid blasted Boehner's decision as an election-year stunt.

"There have already been multiple investigations into this issue and an independent Accountability Review Board is mandated under current law," Reid said in a statement. "For Republicans to waste the American people's time and money staging a partisan political circus instead of focusing on the middle class is simply a bad decision."