Mike Morell said Rice was provided with an unclassified version of events at the U.S. mission in Benghazi that left American Ambassador Chris Stevens and three others dead, according to Rep. Adam Schiff, D-Calif., a member of the panel. Morell made his statements in a closed-door session with the House Intelligence Committee on Thursday.
That initial assessment concluded that an unplanned protest over an anti-Muslim video had escalated into an attack on the American consulate, a description that Rice presented in TV interviews Sunday morning after the attack.
"They gave us the best initial assessments, and those proved inaccurate, but they warned us those assessments were subject to change as they got more information," Schiff said.
Rice's comments have drawn strong criticism, with some Senate Republicans promising to block her nomination if President Barack Obama taps her to replace Secretary of State Hillary Rodham Clinton.
Mr. Obama angrily defended Rice on Wednesday at a White House news conference, calling the complaints outrageous attempts to tarnish her reputation.
Rep. C.A. Dutch Ruppersberger of Maryland, the top Democrat on the Intelligence panel, said Rice was working with the information she was given.
She "was given that same information we received from the administration through the intelligence community. And that's the information she testified to, end of story," Ruppersberger said.
Despite this, Sens. John McCain, R-Ariz., and Lindsey Graham, R-S.C., said they would work to defeat Rice's selection if she is nominated to be the nation's top diplomat. Graham said Wednesday that he couldn't back anyone who is "up to their eyeballs in the Benghazi debacle."
Though Mr. Obama aggressively defended Rice on Wednesday, the president's aides said this should not be seen as a sign that he plans to nominate her for the top job at the State Department. Instead, they said it reflects a frustration within the administration that Rice, a longtime adviser of Mr. Obama, is being unfairly targeted by Republican lawmakers.
The president's aides say Mr. Obama has not made a decision on that job or others opening in his administration, and may not do so until after Thanksgiving.
McCain and Graham have called for the creation of a Watergate-style select committee to investigate the attack, but there is little interest in that step beyond a few GOP lawmakers. Both Senate Majority Leader Harry Reid, D-Nev., and House Speaker John Boehner, R-Ohio, said the existing congressional committees should handle the work.
The Associated Press contributed to this report.