Washington (CNN) -- As scrutiny of a deadly attack on the U.S. consulate in Benghazi, Libya intensifies, Democrats and Republicans on the Senate Foreign Relations Committee sent a letter to the State Department seeking additional details of the incident.
But almost immediately the letter, which was made public Friday, sparked a partisan disagreement. Sen. John Kerry, the Democratic chairman of the committee, accused committee Republicans of trying to exploit it for political reasons.
Kerry said Republicans were wrongly trying to suggest that the Democrats who signed the letter are critical of what has been an evolving explanation about the attack coming from the White House, State Department, Defense Department, and U.S. intelligence agencies.
"Republicans are working overtime to try to exploit a very normal, run-of-the-course administrative letter that we agreed to on a bipartisan basis in our committee simply to get some additional questions put in front of the State Department that are part of their already existing investigation," the Massachusetts senator told Andrea Mitchell in an interview on MSNBC.
"This is not a challenge. It is nothing new. It is not something out of the ordinary. And I agreed to do it as a matter of bipartisanship because we thought these were important questions that people ought to be examining."
In an interview Thursday with CNN's Erin Burnett, Sen. Bob Corker of Tennessee, a GOP member of the committee who has called the shifting explanation of the attack, "Benghazigate," also spoke about the letter.
"Everybody on the Foreign Relations Committee, Republicans and Democrats, wants to know what has happened," he said. "I just find it incredibly strange when in a bipartisan way everyone wants to understand what's happened, but the administration has been unbelievably not forthcoming."
The political back and forth came as the Office of the Director of National Intelligence issued a statement revising its initial assessment that the attack stemmed from a protest against an anti-Muslim film and instead was "a deliberate and organized terrorist assault," by people associated with or sympathetic to al Qaeda, something many congressional Republicans have argued for weeks.
The statement represents the fullest accounting yet of the intelligence community's changed understanding of the attack, and suggests it is trying to distance itself from the political debate over whether the administration is being fully forthcoming about its understanding of events.
The release of such information outlining an ongoing investigation is rare and underscores just how controversial the issue has become.
Democrats believe Republicans are exploiting the issue politically in order to damage President Barack Obama by suggesting the administration was slow to respond to a terrorist attack on its watch. Republicans, meantime, are suspicious Democrats and the White House are trying to protect the president's national security credentials by downplaying the administration's poor handling of the security situation at the diplomatic post in Benghazi, where the U.S. ambassador to Libya and three other Americans were killed.
A Democratic source said Kerry agreed to send the letter -- which expounded on an earlier letter Kerry sent on his own September 17 to the State Department with several questions related to the incident -- after a committee meeting during which GOP members pushed for legislation requiring a formal investigation of what happened. Kerry responded by explaining that there is already a law requiring an investigation by the State Department.
But he agreed to a request from Sen. Johnny Isakson, a Republican from Georgia, to send a letter signed by all the committee members with "additional questions" beyond what Kerry asked in his first letter.
The letter doesn't require a response from the State Department until November 13, a week after the U.S. presidential election.