Sen. John McCain joined other top lawmakers Friday in claiming that the strike on the U.S. Consulate in eastern Libya was a "terrorist attack" and not just a protest spun out of control.
McCain made the comment following an intelligence briefing on Capitol Hill Friday. The Arizona senator said it's hard to know what exactly took place, but stressed that it was not a mob but a calculated act by a small group. The perpetrators, he said, were "terrorists."
The comments by the top Republican on the Senate Armed Services Committee come on top of assertions by House Intelligence Committee Chairman Mike Rogers that the strike was coordinated.
"It just seemed too organized, too well-structured," Rogers, R-Mich., said again Friday, in an interview with Fox News. He said there was "a high degree of command and control," calling it an "act of terror."
Rogers said many factors challenge the claim that the attack was spontaneous.
"I get a little suspect when we conveniently sweep it by -- saying, 'Oh it was spontaneous, next question,'" Rogers said. He acknowledged that "might be the end conclusion" but said that appears extremely unlikely based on available intelligence.
The lawmakers were casting heavy doubt on the narrative, which has lived for days, that the attackers were protesting an anti-Islam film in the U.S. That film has been linked to other demonstrations raging across the Middle East and North Africa all week, but Rogers and McCain suggested Libya was an entirely different situation.
The Libya strike resulted in the death of four Americans, including U.S. Ambassador to Libya Christopher Stevens. The bodies of those killed were returned to the U.S. on Friday, in a ceremony attended by President Obama and Secretary of State Hillary Clinton at Joint Base Andrews in Maryland.
The president is back in Washington Friday after a week on the campaign trail. He briefed top lawmakers on the situation Thursday and has held a series of phone calls with the leaders of Libya and Egypt.
Still, some Republicans have questioned Obama's response, claiming he hasn't shown leadership in this crisis. The Mitt Romney campaign, looking to gain a political edge on the foreign policy front, has taken to calling the administration's handling of the crisis "amateur hour."
But Republicans outside the Romney campaign are also calling for a tougher response out of Obama, and calling into question the explanation that the heavily armed attackers were merely protesting over an anti-Islam film.
"They've got to get out of campaign mode and get into leadership mode," said Rep. Randy Forbes, R-Va., a member of the House Armed Services Committee. "And they really haven't done that, they haven't done it in this situation."
Speculation about the true root of the attack grew following a report in Britain's Independent claiming officials believe the attack was planned, that the State Department may have had warnings in advance and that sensitive documents have since gone missing from the Benghazi consulate.
The Obama administration pushed back on the report.
A spokesman for the Office of the Director of National Intelligence called the article "absolutely wrong."
"We are not aware of any actionable intelligence indicating that an attack on the U.S. Post in Benghazi was planned or imminent," he said.
"We have no intelligence suggesting this attack was premeditated," another U.S. official told FoxNews.com.
Yet a State Department official reportedly told lawmakers Wednesday that he did think the assault was planned.
The Independent report quoted a Libyan troop leader who assisted in the rescue operation that night saying "I don't know how they found the place to carry out the attack. It was planned, the accuracy with which the mortars hit us was too good for any ordinary revolutionaries."
Eastern Libya's deputy interior minister was quoted Thursday saying the attacks may have been timed for the 11th anniversary of the Sept. 11 attacks.
Seth Jones, former adviser at U.S. Special Operations Command, connected it to a call by Al Qaeda's leader to avenge the drone-strike killing of a terror operative in Pakistan.
"This was not just about any sort of a spontaneous revolt. This was an organized attack," he said.
Meanwhile, the top lawmakers on the Senate homeland security committee wrote a letter Friday to the Office of Inspector General for the State Department requesting an investigation into security measures at the U.S. Consulate in Benghazi. Sens. Joseph Lieberman, I-Conn., and Sen. Susan Collins, R-Maine, were the latest officials to express concern about the security protocol at the post.
Outside the growing questions in Washington, the Obama campaign has also aggressively defended itself against sustained criticism by the Romney campaign. It slammed Romney's advisers Friday for their earlier "amateur hour" comment, repeating the argument that Romney is improperly politicizing a sensitive situation.
"It is astonishing that the Romney campaign continues to shamelessly politicize a sensitive international situation," the Obama campaign said in a statement Friday. "The fact is that any president of either party is going to be confronted by crises while in office, and Governor Romney continues to demonstrate that he is not at all prepared to manage them."
Fox News' Catherine Herridge contributed to this report.