Transcript for US bars employee travel to Mexican town after explosion on ferry boat

And we are back now with the security threat in Mexico. With spring break kicking off, we are learning new details about that terrifying ferry explosion at a popular tourist destination. ABC's gio Benitez has all the details. Reporter: Good morning. That was reportedly caused by a bomb, and not an accident. There is a new security alert for Americans traveling to mariplaya del Carmen. In the popular spring break destination, forbidding employees to travel to the town. Embassy officials telling "The associated press," there are new ferries. It was like a giant firework went off. Reporter: One of the bombs exploding, injuring at least 25 people, including five Americans. And now Mexico's biggest TV network, televisa, showing images of the charred remains of that ferry. The network saying the photos show indications of a home made explosive with a detonator and power supply, and reporting anonymous federal sources say, they even found shrapnel. This second device reportedly similar, but more sophisticated, found attached to the bottom of another ferry just days after the first blast. Some of the things we can deduce from the pictures we have seen is these weren't large bombs that were sbeintended to kill a lot of people. They were more likely to slowly sink a boat. Reporter: Princess cruises issuing a rn whiing a warning to its guess saying it has canceled all tours that use ferries, and strongly advise that ferries to the mainland be avoided. I think the Mexican government will be doing a good job to make sure this doesn't happen again. Reporter: And you will remember this new security warning comes after another warning about tainted alcohol there. We have been reporting on those. But this warning is very specific to government employees working in Mexico, not American spring breakers. So they banned those employees from going there, but they are warning American tourists and they want you to get that travel insurance with medical evacuations. They just want you to be very careful. Scary. Coming up here, should

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