Nearly three-quarters of the country's intelligence employees have been furloughed in the government shutdown, putting the country at risk, top intelligence officials said Wednesday.

Because federal law defines essential employees in the agency as those necessary to protect the country from imminent threat, more than 70 percent of intelligence workers are at home until a funding measure is passed, Director of National Intelligence James Clapper told the Senate Judiciary Committee on Wednesday.

"I've been in the intelligence business for about 50 years. I've never seen anything like this," Clapper said. "From my view, I think this — on top of the sequestration cuts that we're already taking — that this seriously damages our ability to protect the safety and security of this nation and its citizens."

Clapper said employees can be shifted around to meet day-to-day needs, but that's a short-term solution that doesn't fix the problem. He said he gave the same assessment to President Obama on Tuesday.

National Security Agency Director Keith Alexander said employees who are still working are focused on "the most significant counterterrorism and other threats that we see and to the support to our military forces in Afghanistan and overseas."

Clapper and Alexander met with Congress on Wednesday for the second time in as many weeks. Like last week's appearance before the Senate Intelligence Committee, they were expected to discuss the a controversial surveillance program that allows the collection of phone records from everyday citizens. However, shutdown talk dominated much of the conversation, as it has across Capitol Hill this week.

Sen. Lindsey Graham, R-S.C., said Clapper's comments regarding staffing levels "scared the hell out of us" and criticized Obama — and his own party — for a political stalemate that has left the country vulnerable.

"There are shutdowns before 9/11 and there are shutdowns after 9/11. And there's a huge difference," Graham said. "For the president of the United States, for our House Democrats to not negotiate, is irresponsible. For our Republican Party not to try to find a way to end this mess is irresponsible. So I hope that the president will do more than watch."

President Obama signed a measure Monday night that ensures military personnel receive pay in a timely matter regardless of the shutdown. Clapper said he "would be a strong supporter" of extending that to combat-support agencies, like the NSA, to keep staff levels close to 100 percent.

Sen. Jeff Flake, R-Ariz., said that if Clapper pressured Obama to take this step, Republicans and Democrats in both houses would "move expeditiously to" fund intelligence workers.

"If the situation is as dire as you say," Flake said, "and I believe that it probably is, then I believe it would warrant the president saying, OK, whatever you do, however long this is going to last, we've got to make sure that we're collecting the necessary intelligence."