Officials from multiple agencies tell ABC News that after five days of the U.S. government pushing its law enforcement and intelligence agencies to full tilt, no significant  evidence has turned up to confirm the recent terror threat allegedly aimed at Washington DC and New York.

While some officials remain concerned about the rest of this week in particular,  a number of sources say they are almost ready  to exhale a little.

“We are getting close to a sigh of relief,” one official said.

Despite the threat information not being confirmed at this time FBI Director Robert Mueller and Homeland Security  Secretary Janet Napolitano said today that  the threat was still ongoing.

“The threat has not been resolved and until it is resolved it is an outstanding threat that we are following up on. Even though Sept.  11 has now passed, we do not believe that  that necessarily means we should back down,”  Mueller told  the Senate Homeland Security and Government Affairs Committee.

“[The FBI], Department of Homeland Security, NCTC [The National Counterterrorism Center], the intelligence agencies are pursuing that as heavily as we have over the last several days and will continue to do so until it’s resolved,” Mueller said.

“We consider it an ongoing threat and we continue to lean forward into confirming that threat,” Napolitano said.

Last week DHS and the FBI issued a joint bulletin based on threat information from a credible source that there was an ongoing plot to detonate vehicle-born bombs in New York City or Washington, DC.  The threat prompted a massive police show of force in the cities and sent the intelligence community into a race to try and run the threat information to ground.

Mueller told the Senate Committee today some actions that the FBI has taken. “Since we first had word of that threat we have conducted hundreds of interviews.  We have been pursuing a number of leads and consequently there. As a  result of that, we’ve been now able to eliminate some aspects where we  thought that we ought to be looking in order to determine whether it was indeed a valid threat.  But there’s still work to be done.”

Matthew Olsen, the recently confirmed director of the National Counterterrorism Center told the Senate panel, “We’re not prepared to say that it’s been resolved and will continue to work to analyze it and share information about it.”