The U.S. Embassy in Mexico said Thursday that a security alert about the Caribbean resort of Playa del Carmen was not related to an explosion on a ferry that injured at least two dozen people.
The embassy did not specify what kind of security threat it had been informed of in the resort, which is near Cancun, Cozumel and Tulum.
But it did say that "we do not have information relating the ferry explosion to the security threat in Playa del Carmen."
That threatened to complicate matters for one of Mexico's key tourism sites, since the ferry threats had at least already been known and, according to Mexican officials, were related to "business issues" with the ferry company.
Now it appears a different threat also exists. The area has also been hit, albeit infrequently, by drug violence, and the violent Jalisco cartel has been seen moving into the area.
But it was not clear if that was in any way related to the security alert issued Wednesday by the Embassy.
The alert included an indefinite ban on travel to Playa del Carmen by U.S. government employees. It said the U.S. consular agency there "will be closed until further notice."
Mexican officials said the city is safe, despite the U.S. alert.
"All tourism and economic activity in Playa del Carmen continues in a normal manner," the government of Quintana Roo state said in a statement, noting that hotel occupancy at the resort was 80 percent.
It said President Enrique Pena Nieto attended an ocean conservation conference in Playa del Carmen on Thursday.
"We do not know why the U.S. government decided to emit this alert," the state government said.
A Feb. 21 explosion on a ferry that runs between Playa del Carmen and Cozumel injured 19 Mexicans and at least five U.S. citizens.
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.
And last week, undetonated explosive devices were found on another boat owned by the same ferry company.
State prosecutors say the ferry incidents are under investigation. Local media say officials are examining several possible motives, including the possibility the bombing may have been related to an insurance policy.
The ferry company has not responded to requests for comment. But on March 4, the company issued a statement saying that "referring to this as an attack from inside the company is a very low, morally unfounded act, which we categorically deny."
While the Caribbean coast — especially Cancun and the area south known as the "Riviera Maya" — has been largely spared the drug violence affecting other areas, there have been killings.
Last week four gunmen burst into a hospital in Cancun and shot to death a drug gang suspect and his wife.
In January 2017, gunmen attacked the state prosecutors' office in Cancun, killing four people. A day before that, a shooting at a music festival in Playa del Carmen left three foreigners and two Mexicans dead.