At least one congressional Democrat came to the administration's defense, urging lawmakers to afford investigators ample time to review the incident.
"We shouldn't do anything to compromise the ongoing effort to hunt down the attackers or the ongoing review of this attack by the independent accountability board," said Rep. Elijah Cummings of Maryland, the top Democrat on the House Committee on Oversight and Government Reform. "We need to let these investigations go forward and only then draw conclusions."
White House press secretary Jay Carney told reporters today, "There was a variety of information coming in" in the aftermath of the attack as the intelligence community assessed strands of information to "make judgments about what happened and who was responsible."
White House officials added that the alerts were not definitive, noting that Ansar al-Sharia denied responsibility for the attack six days later.
State Department spokeswoman Victoria Nuland confirmed that the email mentioning Ansar al-Sharia was sent by the State Department's operations center, whose role is to collect public, unclassified information and disseminate it to senior administration officials in "real time."
Nuland added that the operations center sends tens of emails each day to keep administration officials informed of "what's out there in the public," and though it uses some judgment in sending out summaries of what various extremist groups and press reports are saying, the summaries should not be considered analysis.
"They report what they get. So if they reported, 'embassy in Tripoli says,' then it is based on something that embassy in Tripoli said," she said. "Whether that can be right or that could be wrong is something to be evaluated later."
Nuland confirmed that assessments on the reports are made by the intelligence community.
ABC News' Jake Tapper contributed to this report.