Police in the southern U.S. state of Florida have closed a 20-mile stretch of a major east-west highway stopping two cars and detaining three men after receiving a tip on a possible terrorist threat.

The cars were stopped early this Friday morning on the famous "Alligator Alley" which runs across the Florida wetlands known as "The Everglades."

Bomb sniffing dogs were brought in and alerted authorities to suspicious material in both cars. News reports say that a bag or backpack was removed from one of the cars and may have been detonated.

Police in the neighboring state of Georgia were tipped off on Thursday when a waitress reported overhearing three men talking about what she believed to be a terrorist plot.

Authorities in both states spent the night searching for the men who are reported to be of Middle Eastern descent.