Authorities at the Port of Miami have given the "all clear," and say a package that initially tested positive for plastic explosives was found to not contain a bomb.

Coast Guard authorities say the package, which was scheduled to be loaded onto Caribbean International's `Majesty of the Seas' cruise ship, was flagged by scanning instruments Monday as it came off a truck.

The Coast Guard says it tested the package and detected military grade plastic explosives, known as C-4.

The package was destroyed by the local bomb squad as a precaution. When police examined the remains they determined the package contained sprinkler parts. It is not known how it came into contact with explosives.

The incident is the second false alarm in two days at the Port of Miami. Sunday, three men of Middle Eastern descent were detained while trying to drive a truck into the port's cargo area. Officials later released the men, blaming the incident on miscommunication.

Some information for this report was provided by AP and Reuters.