A police official has said that the van attack in Barcelona that left 13 people dead and at least 100 people wounded was connected to an explosion in the city the previous day that left one person dead.
The Islamic State group has claimed responsibility for the attack in Barcelona via its Amaq news agency.
The president of the Spanish region in which Barcelona is located said that two arrests have been made after the Barcelona van attack. He also confirmed that 13 people were killed and at least 80 were wounded.
A Catalan official said 13 were killed in the Barcelona van attack and more than 50 have been injured.
Police confirmed that a suspect has been arrested, the BBC reported.
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A Barcelona broadcaster reported that a man believed to be the van's driver was stuck in a bar that was surrounded by police.
Tv3 also reported that the Spanish passport of a person of Moroccan origin was found at the attack's scene.
Police posted up outside a bar called Rey de Istanbul, according to the television station, but would not confirm a cornered suspect was inside.
Barcelona's El Pais newspaper reported earlier that police were seeking more than one suspect in an unnamed bar.
A regional government official reportedly said that all public festivities in Barcelona are temporarily canceled after Thursday's incident.
President Trump condemned the Barcelona van attack on Twitter.
Secretary of State Rex Tillerson issued a statement on the Barcelona van attack.
"I'd like to start by acknowledging the incident in Barcelona which has the hallmarks it appears of yet another terrorist attack," Tillerson said. "We offer our condolences to the loss of life and the injuries that have occurred to so many innocent people yet again. We will continue to monitor the situation. We stand ready to assist law enforcement, national security authorities in Spain. Our consulates in Barcelona and our entire mission Spain team are currently assisting Americans in Spain who are affected by these events. We ask U.S. citizens in the area to let your loved ones know you are safe. Terrorists around the world should know the United States and our allies are resolved to find you and bring you to justice."
WARNING: This item contains material that some viewers may find disturbing due to the graphic nature.
An Instagram post shows a number of people on the ground and debris from when the van ran them over.
London Mayor Sadiq Khan on Thursday tweeted support for Barcelona after the incident, which he called a "barbaric terrorist attack."
My thoughts are with the victims of this barbaric terrorist attack in the great city of Barcelona and with their brave emergency services.— Sadiq Khan (@SadiqKhan) August 17, 2017
A government official in Barcelona, Spain on Thursday reportedly confirmed one person had died and 32 more had been injured after a van plowed into crowds there.
"Unfortunately the number of fatalities will likely rise," Joaquim Forn, Catalonia's regional interior chief said during a press conference.
Media in Barcelona are reporting that up to 13 died in the incident, while the city's police said that 10 of the wounded are seriously hurt on Twitter.
Police in Barcelona, Spain on Thursday said they have located a van which they believe was used to ram crowds of people there, according to CBS News.
CBS News reported that the vehicle's driver remains missing, amid Spanish media reports that two armed male suspects are bunkering in a Barcelona bar.
A White House official said chief of staff John Kelly is "aware of the situation, and keeping the President abreast" as it develops, according to pool reports.
First lady Melania Trump offered "thoughts and prayers" to Barcelona on Twitter.
Police in Spain on Thursday called a van ramming into crowds in Barcelona a terror attack as local media reported that 13 people had died in the incident.
Emergency vehicles rushed to the scene in the Las Ramblas district of Barcelona where a van plowed into a crowd.
This video by @Pablo_Morante shows police rushing to the scene.
Catalonia's government confirmed one person had died and 17 others were injured, with seven in serious condition in the hospital, CNN reported.
Barcelona police told CNN that the van crash is "most likely" a terrorist incident.
Armed police officers were seen patrolling the streets of central Barcelona on Thursday after a van slammed into pedestrians in a historic district.
MSNBC reported on air that the White House is keeping President Trump aware of the situation as it unfolds.
A Catalan police spokesperson told CNN that the van had caused a "number of deaths" and "many injuries" after ramming into crowds in Barcelona.
Spanish police sources say there is an ongoing hostage situation in Barcelona following the van incident, ABC News reported.
Spain's El Periodico newspaper reported that two male suspects were reportedly armed in the Barcelona bar and that gunfire had been heard in the surrounding area.
The publication did not identify the source of its information, however, and it is unclear if the two events are related.
Spanish Prime Minister Mariano Rajoy said he is in contact with authorities, adding that the top priority is helping those wounded.
Reuters reported that Spanish media said at least two people had died, noting a police spokesman had also declined to confirm any deaths or if the incident is terrorism.
Here's some footage from the scene of the van incident.
Spain's El Pais Newspaper on Thursday cited police sources in Barcelona to report that perpetrators who drove a crowd into pedestrians there were hiding in a local bar.
Marc Esparcia, a 20-year-old student who lives in Barcelona, told the BBC that "there was a loud noise and everybody ran for cover."
"There were a lot [of] people, lots of families [at the site]," he said. "This is one of the most visited sites in Barcelona."
"I think several people were hit," Esparcia added. "It was horrible. There was panic. Terrible."
Steven Turner, who works in the area, told the BBC that "people in my office saw a van ramming into people on La Ramblas."
"I saw three or four people lying on the ground," he said. "There are lots of ambulances and armed police with assault rifles right now."
Europe has experienced repeated attacks involving cars plowing into crowds since July 2016, with instances in Berlin, London, Stockholm, and Nice that had killed over 100 people.
Reuters reported that recent weeks have seen Barcelona, a city which draws roughly 11 million visitors annually, defaced with recurring anti-tourist graffiti.
One video reportedly released under the slogan "tourism kills neighborhoods" depicts several hooded individuals halting a tourist bus in Barcelona.
The individuals then slash the vehicle's tires and spray-painted the windshields during the footage.
Footage posted on Instagram showed crowds tending to at least three fallen individuals, with the extent of their injuries unclear as police arrived at the scene.
Reuters reported that local media said two people were killed in the incident, while two armed men had entered a restaurant in Barcelona after the crash.
El Pais newspaper reported that the vehicle's driver fled on foot after striking down dozens of people.
Barcelona police are calling the van incident a "terrorist attack," Agence France-Presse reported.
Police in Barcelona, Spain, on Thursday said a white van mounted a sidewalk in the city’s Las Ramblas district, striking several people there.
A Catalan police spokesman told CNN that Las Ramblas, which is a popular tourist destination, has been sealed off following the incident.
Police added that they believe several people had been injured, noting they were unable to give a motive for the incident.
Reuters reported that Catalan emergency services requested the closure of metro and train stations in the vicinity of the scene. Barcelona police also told people to avoid the area.
Some Twitter users on Thursday began sharing video of the incident in Las Ramblas, with footage showing multiple police vehicles arriving there.
Other people on the social media platform voiced alarm at the incident, which police are currently investigating and have not yet determined a cause for.
Thinking of anybody injured in or affected by the attack in Barcelona. I hope that one day these people will be stopped 💔— Cait (@caitysmyth) August 17, 2017
At least one person on Twitter tried estimating the number of people who had been hurt in Thursday's unexpected event.
This story is developing…
The Associated Press contributed to this report.