ISIS has reportedly claimed responsibility for an attack where a van plowed into a crowd in a busy square in Barcelona, Spain, on Thursday, with the police reporting 13 deaths

The police are calling the incident a terrorist attack and have arrested two suspects

Police killed five suspected attackers during a counterterrorism operation in Cambrils, south of Barcelona, early Friday morning. Police said they believe the attackers may be linked to the van attack.

Police have two suspects in custody after a van crashed into a crowd of pedestrians in a tourist-heavy district killing at least 13 on Thursday in Barcelona, Spain, Catalan President Carles Puigdemont said.

The Catalan police are calling the earlier incident in Barcelona a terrorist attack and have confirmed at least 13 deaths and over 100 injuries. At least 18 nationalities are among the attack victims, authorities said. In a message on ISIS' news service, the terror group claimed responsibility for the attack, though authorities have yet to confirm a link.

Police initially said the van connected to the attack was rented by a man named Driss Oukabir, reportedly a Moroccan citizen living in France legally. El Pais, a Spanish-language newspaper, said Oukabir turned himself into police, claiming he had nothing to do with the attack and that his ID was stolen and planted near the scene.

It's unclear whether the police have identified additional suspects in the crash. The police dismissed reports from multiple outlets that two armed men had barricaded themselves in a bar near the site of the crash as rumors, though officers were still apparently conducting door-to-door searches as the area around the crash site remained on lockdown for hours.

Five alleged attackers were killed in a separate counterterrorism operation in the town of Cambrils, about 90 minutes south of Barcelona, early Friday morning. Catalan police said they believe the suspects in Cambrils were linked to the Barcelona van attack and a house explosion in the town of Alcanar that happened on Wednesday. Police confirmed Moussa Oukabir, a key suspect in the attack, was one of the attackers killed, reports the BBC.

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Police checkpoint attack and a house explosion

Reuters, citing police sources, said a second van linked to the crash was found in a small town outside Barcelona. The news agency noted earlier reports from local media suggesting that a second van may have been rented as a getaway vehicle.

A driver of a different vehicle ran over two police officers at a checkpoint in Barcelona, The Associated Press reports, though it's not clear whether this was related to the earlier attack. Associated Press reports that the driver was killed in a shootout with the police.

Authorities cited by Reuters said a house explosion hours before the van attack killed one person in Alcanar, about 100 kilometers (62 miles) southwest of Barcelona. Officials say the incident may be connected. The Telegraph reported that police found 20 canisters of butane and propane gas among the rubble.

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A chaotic scene

The police said the chaos in Barcelona started when a white van mounted a sidewalk on Plaza de Catalunya, a popular square in Barcelona. The Spanish-language newspaper El País said the driver of the van fled on foot after "mowing down" dozens of people.

"There's a very heavy police presence and what they've been doing is going from establishment to establishment knocking on the doors, knocking on the shutters," John Ward, a resident of Las Ramblas, a pedestrian-heavy street near Plaza de Catalunya, told the BBC. "Now nobody is moving on La Ramblas unless they're under police escort."