BARCELONA — A white van slammed into crowds on a crowded pedestrian mall Thursday in the popular Las Ramblas tourist district, killing at least 13 people and injuring 100 in what Spanish police called a terror attack.

The attack is the latest in a chilling trend of vehicular terrorism that requires little organization, manpower or technological know-how.

Vehicles have been used to plow into pedestrians in the United Kingdom twice this year, including a June attack on London Bridge that killed eight people and a March attack on Westminster Bridge where four pedestrians and one police officer were killed. In late December, a truck plowed into a Christmas market in Berlin, killing 12 people and wounding nearly 50 others.

Maghrebi Driss Oukabir, alleged to have rented the van which was used to crashed into pedestrians in Las Ramblas, downtown Barcelona, Spain, on August 17, 2017.   (Photo: Spanish National Police/ Handout, EPA)

Police detained two people in connection with the attack, according to Carles Puigdemont, president of Spain’s Catalonia region.

Catalan regional police identified Oukabir Driss, 28, a Moroccan citizen and legal resident in Spain, as the man who allegedly rented the van used to crash into the pedestrians. Police said they were "treating him as a terrorist."

The U.S.-based based SITE Intelligence Group that tracks terrorist networks said the Amaq News agency, which is linked to the Islamic State, reported that the extremist group had claimed responsibility for the attack.

PHOTOS: Deadly Barcelona terror attack

The attack unfolded Thursday afternoon as pedestrians filled the bustling Las Ramblas district lined with stalls and shops in the center of Barcelona. August is peak tourist season in Barcelona, which is a popular destination for Americans.

The van entered Las Ramblas at the northern edge, jumped the sidewalk and barreled into the central pedestrian zone. It careened more than 600 yards through the pedestrian section, zig-zagging through the crowds, according to Rac1. It came to stop atop the famous Joan Miró mosaic, where the attackers fled.

State-owned broadcaster RTVE reported that investigators think two vans were used — one for the attack and a second as a getaway vehicle, according to the Associated Press.

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"We can confirm this was a terror attack. The counter-terror protocol has been activated," the Catalan police tweeted.

Laia González, 22, a recent university graduate who lives nearby, was getting ready to go out and shop with her parents when they heard screaming.

“We went out on the balcony and saw many people running, stumbling over each other, screaming in absolute horror, going inside shops, and shops shutting down," she said. "All you could hear was screaming and the loud noise of (store's) metallic blinds.”

Albert Tort, 47, a nurse who lives in the area, told the Spanish newspaper, El Pais, the scene of the carnage was a "real disaster."

In Washington, the White House said President Trump had been alerted to the unfolding situation. He said on Twitter than the U.S. condemns the terror attack and "will do whatever is necessary to help. Be tough & strong, we love you!"

The CIA warned Barcelona police two months ago of a possible terrorist attack targeting Las Ramblas, according to El Periodico, a Catalunya daily newspaper.

El Periodico reported that Barcelona has been on alert since last year when the Islamic State showed a picture of La Sagrada Familia — the most famous church in Barcelona — among other notable landmarks, such as the Coliseum in Rome, Big Ben in London and the Statue of Liberty in New York, as high risk targets.