The US State Department issued a security alert to its citizens on Sunday, telling them to exercise “heightened caution” if they are in Barcelona because of the potential for a terrorist attack in the popular area of La Rambla during Christmas and New Year’s.

“Exercise heightened caution around areas of vehicle movement, including buses, in the Las Ramblas area of Barcelona during Christmas and New Year’s. Terrorists may attack with little or no warning, targeting tourist locations, transportation hubs, and other public areas,” says the agency on its official Twitter account.

#Spain: Exercise heightened caution around areas of vehicle movement, including buses, in the Las Ramblas area of Barcelona during Christmas and New Year’s. Terrorists may attack with little or no warning, targeting tourist locations, transportation hubs, and other public areas. pic.twitter.com/MPGiZwMwxq — Travel - State Dept (@TravelGov) December 23, 2018

As a result of the information that they have received, the Catalan police, the Mossos d’Esquadra, are now looking for a man who has been identified as B. L., 30, from Casablanca, Morocco. This man is in possession of a bus driver’s license and he has a police record in Spain for insulting a member of the Civil Guard at Málaga airport in 2006.

Barcelona’s La Rambla was the site of a major terrorist attack in August of last year, when a Jihadist rammed a rental van into pedestrians along the busy thoroughfare, killing 16 and injuring 131.

The police are currently carrying out checks on bus and minibus drivers in the center of Barcelona and monitoring car rental companies in a bid to locate the potential suspect. There is no indication that he is currently on Spanish territory.

On August 18, 2017 La Rambla was the site of a terrorist attack when a van plowed into a crowd

The regional police will reinforce their presence on La Rambla over the holidays with extra Mossos on duty and added inspections of the area. Potential targets such as the Sagrada Familia basilica will also have extra security.

These kinds of alerts are common over the Christmas season and the Interior Ministry has the terror alert set at level 4 on a scale of 5.

On August 18, 2017 a man named Younes Abouyaaqoub drove a rental van into a crowd on La Rambla, in the worst terrorist attack in Spain since the March 2004 Madrid train bombings that killed 193 people and left around 1,700 injured.

Nine hours later, a similar attack took place in Cambrils, south of Barcelona, where attackers in a vehicle mowed down six people.