Sen. Saxby Chambliss (R-Ga.), the vice chairman of the Senate Intelligence Committee, said Sunday that current security threats remind him of the time before the 9/11 attacks.
Unspecified security concerns led to a global travel warning for Americans and the weekend closure of many embassies in the Muslim world on Sunday.
"The one thing we can talk about is there's been an awful lot of chatter out there," Chambliss said on "Meet The Press." "Chatter means conversation among terrorists about the planning that's going on. It's very reminiscent of what we saw pre-9/11. We didn't take heed on 9/11 in the way that we should, but here I think it's very important that we do take the right kind of planning."
Chambliss cited the end of Ramadan and the approaching anniversary of 9/11 as possible factors in the timing of an attack.
"We're paying very, very close attention to the chatter that's going on. This is the most serious threat that I've seen in the past several years," he said.
Gen. Michael Hayden, the former director of the NSA and CIA, said on "Fox News Sunday" that while he didn't have inside knowledge of the current threats, the administration's decision to shut down embassies pointed to a serious situation.
"I can only imagine what it would have taken while I was in government in terms of the stack of evidence it would require" to take such action, he said, although he noted that "the announcement itself may also be designed to interrupt al Qaeda planning."
Both Hayden and Chambliss said the threats demonstrated the importance of large-scale NSA intelligence-gathering programs.
"If we did not have these programs, then we simply wouldn't be able to listen in on the bad guys," Chambliss said, adding that some of the intelligence gathered was from a surveillance program exposed by Edward Snowden.
Sen. Dick Durbin (D-Ill.), however, argued on "Meet The Press" that the scope of such programs was too broad.
“Do we need to collect all of the phone records of all of the people living in America for five years so that if we’re going to target one particular person we’re ready to jump on it?” he asked on Sunday. "Does the government need all this information on everybody in the country?"