By Mark Hosenball and Patricia Zengerle
WASHINGTON (Reuters) - Fearing they could miss important intelligence, U.S. spy agencies are planning to call back to work some of the thousands of civilian workers who have been temporarily laid off as a result of this week's federal government shutdown.
Director of National Intelligence James Clapper has already authorized chiefs of the 16 U.S. spy agencies he supervises to make revisions in their furlough arrangements, Clapper's spokesman Shawn Turner said.
"The impact of the shutdown on the Intelligence Community's mission is not static, it's cumulative. The employees who are on the job are stretched thin. They're focused on the most critical security needs," Turner said in an email on Wednesday.
"However, as this goes on and the security environment changes, we will need to make adjustments to the number of people we have working," Turner said. Precisely which agencies will call back workers and how many is unclear.
Turner and other officials familiar with the issue could not immediately explain how much legal leeway spy chiefs had to recall furloughed employees. One official said agencies were generally authorized to keep on board personnel needed to ensure the shutdown does not jeopardize lives or national security.
Another official said intelligence chiefs "should be freaking out" over the current level of furloughs because the public will turn on them "if anything happens."
On Tuesday, Dianne Feinstein, the chair of the Senate Intelligence Committee, said spy agencies were under instructions to place 72 percent of their civilian work forces on furlough during the shutdown, which has been caused by a legislative deadlock between the Democratic-controlled Senate and Republican-controlled House of Representatives.
Feinstein said good intelligence required that CIA officers overseas meet with human sources and that "technical wizards ... collect signals and imagery information."
While she did not explicitly say that the shutdown had stopped CIA case officers meeting informants or caused the National Security Agency to curtail electronic eavesdropping, other officials said CIA processing of intelligence from human sources was likely to suffer as a result of the shutdown.
Officials said that as many as 12,500 of the CIA's civilian work force, which is believed to total around 20,000, were initially placed on furlough.
At a Senate hearing on Wednesday, Clapper and other spy chiefs warned that the longer the shutdown continued, the more national security could be placed in jeopardy.
"I've been in the intelligence business for about 50 years. I've never seen anything like this," he told the hearing on U.S. electronic eavesdropping programs at the Senate Judiciary Committee.
"This (the shutdown) affects our global capability to support the military, to support diplomacy and foreign policy matters. The danger here is that this will accumulate over time. The damage will be insidious, so each day that goes by the jeopardy increases," he said.
Feinstein said Clapper had sent to Capitol Hill a detailed account of how the shutdown "will cripple" spy agencies, including the CIA and the NSA, as well as the National Reconnaissance Office and the National Geospatial Intelligence Agency which process information from spy satellites.
Some spy agencies, such as NSA and the Defense Intelligence Agency, are staffed by large numbers of uniformed military personnel, who are not affected by the government shutdown. But Feinstein said every agency she mentioned "will lose the majority of its workforce." She did not give specific numbers.
At Wednesday's Senate committee hearing, the director of the NSA, General Keith Alexander, said his agency risked an exodus of highly skilled personnel the longer the shutdown continued. He said furloughs were hurting morale and the NSA risked losing thousands of PhDs, computer scientists and mathematicians forced off the job by the shutdown.
(Editing by Alistair Bell and David Brunnstrom)