The Obama administration faced increased pressure Thursday to provide more information about the attack on the U.S. Consulate in Libya that left an ambassador and three other Americans dead.

Senate Foreign Relations Committee Chairman John Kerry John Forbes KerryPresident Trump faces Herculean task in first debate Trump, Biden have one debate goal: Don't lose Trump-Biden debate: High risk vs. low expectations MORE (D-Mass.) was circulating a letter Senate aides said would be signed by members of both parties asking for more information and another briefing on Libya — a development Republicans described as a significant shift from what had been a partisan fight.

“It's my understanding today that all members of the Foreign Relations Committee — both Democrats and Republicans — are asking the administration for answers,” Sen. Bob Corker Robert (Bob) Phillips CorkerHas Congress captured Russia policy? Tennessee primary battle turns nasty for Republicans Cheney clashes with Trump MORE (R-Tenn.) said. “So this is now something that certainly could never be colored as partisan.”

ADVERTISEMENT

GOP pressure also ratcheted up a notch after Secretary of Stateon Wednesday drew a link between al Qaeda-affiliated groups and the Libya attack.

Republicans argued Clinton’s comments at a meeting of leaders attending the United Nations General Assembly underlined their arguments that the administration’s account of the incident has shifted and that officials were too quick to blame the death of U.S. Ambassador Chris Stevens on a protest gone wrong.

Sen. John McCain John Sidney McCainAmerica's presence in Cam Ranh Bay should be more than occasional Meghan McCain, husband welcome first baby girl, Liberty Sage McCain Domenech The Hill's Morning Report - Sponsored by JobsOhio - Showdown: Trump-Biden debate likely to be nasty MORE (R-Ariz.), perhaps the administration’s most aggressive critic on foreign policy, said it was “unbelievable” and “disgraceful” that the administration had blamed protests of an anti-Islamic video for the attack.

Asked by CBS News why the administration might have emphasized the video, McCain argued it was due to election-year concerns that blaming al Qaeda would downplay Obama’s success in the war on terror.

“Some allege that maybe it’s because they’re trying to convey to the American people that al Qaeda is no longer a threat, and that when Osama bin Laden left that was the case, but the reality is that al Qaeda is well and thriving in some places,” McCain said.

Foreign policy and national security have long been strengths for Obama in the campaign, but a new poll suggested he could be vulnerable because of the recent events.

The Bloomberg News poll conducted after the Benghazi attack found that GOP presidential nominee Mitt Romney had overtaken Obama on “being tough on terrorism,” 48-42 percent.

In the hours after Stevens’s death, Romney hit the White House hard for blaming the video for the attack. He backed off after coming under criticism himself, but has since sought to use the Libya violence as an example of Obama’s failed leadership.

White House officials pushed back Thursday at the latest GOP criticism, while Obama’s campaign said it wasn’t worried about what it called an effort to politicize the issue.

“Every time Gov. Romney has attempted to dip his toe in the foreign policy waters, it's been an unmitigated disaster,” said Jen Psaki, Obama's traveling press secretary.

White House press secretary Jay Carney said Thursday that Obama believes the attack in Libya was an act of terrorism, but referred all specific questions on the investigation in Libya to the FBI.

He also defended the administration’s handling of the issue, insisting that at every step of the way, the administration had provided information to the media and general public about the attack “based on the best intelligence we have and the assessments of our intelligence community.”

While Democrats haven’t openly criticized the administration’s response in Libya, they are starting to seek more answers as questions continue to mount.

A Senate aide said the Foreign Relations panel’s letter to Thomas Nides, deputy secretary of State for Management and Resources, would be signed by the entire committee and would ask for more information and a full briefing the week after the Senate returns in November.

While Clinton on Wednesday suggested al Qaeda of the Maghreb might have been involved in the attack, State Department officials have said an investigation is ongoing and Defense Secretary Leon Panetta on Thursday said it’s too soon to know who is responsible.

The FBI is in Libya investigating the attack, but agents reportedly have not gone to Benghazi or the crime scene.

“It pretty clearly was a terrorist attack because a group of terrorists obviously conducted that attack on the consulate and against our individuals,” Panetta said at a Pentagon press briefing. “What terrorists were involved, I think, still remains to be determined by the investigation. But it clearly was a group of terrorists who conducted that attack against that facility.”

Asked whether it took a day or longer for the administration to label it a terrorist attack, Panetta said that it “took awhile to really get some of the feedback from what exactly happened at that location.”

Appearing with Panetta, Chairman of the Joint Chiefs of Staff Gen. Martin Dempsey said Thursday there was a “thread of intelligence reporting” that groups in the area were seeking to coalesce, but nothing specifically tied to the consulate.

“There wasn't anything specific and certainly not a specific threat to the consulate that I'm aware of,” Dempsey said.