FBI asks agencies to watch Memphis bridges

LITTLE ROCK, Ark. -- The FBI asked law officers assigned to areas around the Mississippi River bridges at Memphis, Tennessee, to help keep an eye on the spans after a vague threat came in warning that one would be blown up.

FBI spokesman Christopher M. Allen said Tuesday from Washington the threat was "unsubstantiated." The agency's Memphis office alerted local police as a matter of routine but there was no specific threat to address, Memphis Special Agent D.O. Little said Tuesday.

"It was just an anonymous threat with no actual intelligence of an attack," Little said.

Two cross-country routes traverse the Mississippi River at Memphis -- Interstates 40 and 55 -- and both remained open. Each bridge carries about 40,000 vehicles daily.

The FBI advisory, sent Monday, cited a threat to the "Memphis-Arkansas" bridge from an Islamic State cell in Memphis.

The Arkansas Department of Emergency Management said the threat had not reached a level requiring it to put anyone on standby, as it would if bad weather was approaching.

"We're not on any heightened alert," spokesman Rick Fahr said.

He said threats that include specifics are rare.

Highway officials reviewed contingency plans.

"This is no different from it is in the event of an earthquake or an ice storm," said Danny Straessle, a spokesman for the Arkansas Highway and Transportation Department.