"It was clearly a terror attack, meant to kill as many people as possible", Josep Lluis Trapero, a senior police official for Spain's Catalonia region told reporters late Thursday.
Replying to a Twitter inquiry from a Portland television about whether the team was OK, Oregon State head coach Wayne Tinkle responded: "Yes we are, happened directly in front of our hotel while we were having a team meal in the restaurant, so senseless and sad!"
Spanish police did not immediately give details on the driver or a possible reason for the incident, but described the aftermath as "massive".
A white van with blue markings accelerated into scores of people enjoying a late afternoon stroll on Las Ramblas, a predominantly pedestrian zone located in the heart of the Catalan capital.
The vehicle careered into terrified pedestrians in the busy tree-lined promenade, one of the most popular parts of the city.
Oukabir's exact alleged role - whether he was the attacker, an accomplice, or has some other link to the attack - has not yet been clarified by authorities.
Ali Shirzainia was cycling when he saw the van drive past him. People started running and jumping into shops.
"I heard a lot of people screaming and then I saw the van going down the boulevard", another witness, Miguel Angel Rizo, told The Associated Press.
Real Madrid roll over Barça to win Spanish Super Cup
But Zidane has stressed that Barcelona will be competitive once the La Liga season gets underway this weekend. Karim Benzema later flicked up Marcelo's cross to fire home a second before the break.
Catalan police tweeted that the search for the perpetrator of what they called a "massive trampling" was continuing as of 6 p.m. local time (10 a.m. MDT). Police later said the driver was still on the run, according to the Telegraph in Britain.
Two other suspects have been arrested.
People flee from the scene after a white van jumped the sidewalk in the historic Las Ramblas district of Barcelona, Spain, crashing into a summer crowd of residents and tourists Thursday, Aug. 17, 2017.
El Periodico reported that Barcelona has been on alert since previous year when the Islamic State showed a picture of La Sagrada Familia - one of the most famous churches in Barcelona - among other notable landmarks such as the Coliseum in Rome, Big Ben in London and the Statue of Liberty in NY as high risk targets.
Prime Minister Mariano Rajo said he was in contact with authorities, and the priority was to attend to the injured. At least 80 people were in hospital, with 15 of them in serious condition.
Local officials have said that the number of dead is "bound to rise".
Foreign Secretary Boris Johnson said: "Concerned and saddened by #Barcelona attack". Six civilians and a police officer were injured in the Cambrils operation.
"We were also told that they took people hostage in nearby bars". Their exhibition game for tonight has been cancelled and the team will return to Clemson as previously scheduled tomorrow morning.