USA government employees are not allowed to travel between cities after dark in many parts of Mexico.
He also says that threats are nothing new, and haven't prevented people from traveling to other countries with warnings in the past.
The state department is warning people about the dangers of traveling to a popular tourist town in Mexico.
Now the department says their information about a security threat is changing.
Originally the state department wanted people to think twice about going to Playa del Carmen, especially with spring break coming up.
The State Department first included the Riviera Maya, where Playa del Carmen is located, on its travel warning list in August a year ago.
But it was not clear if that was in any way related to the security alert issued Wednesday by the Embassy.
"There is information that there could be a violent attack in the next few days", said Eric Olden, the Director of Wilson Center Latin America Program and expert of security issues in Mexico.
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Recent violence, like an explosion of a tourist ferry last month, has government officials warning Americans to stay out of Playa Del Carmen, Mexico.
United States officials have been in touch with Mexican law enforcement officials who are leading the investigation, Nauert said at a news briefing Thursday. The explosion took place while passengers were disembarking the ferry.
Two more explosive devices were found attached to another ferry in Cozumel this week.
Both incidents are still under investigation with no apparent motive released to the public yet.
After that, the U.S. Embassy barred employees from taking the ferries to Cozumel, one of the world's busiest cruise ship ports of call.
"Police forces are working day and night to maintain the calmness of the residents and visitors of Quintana Roo, ' said state governor Carlos Joaquín in a statement".
The state department says people from the US should avoid those neighborhoods until further notice. The states are Colima, Guerrero, Michoacan, Sinaloa, and Tamaulipas; Quintana Roo, the state where Playa del Carmen is located, is still at a level two.