Joaquim Forn, a senior official at the Catalan government, said that 13 people had died and more than 50 had been injured.
The Mossos d’Esquadra, the Catalan regional police confirmed it had made one arrest, but denied reports that an attacker had taken refuge inside a bar.
Mariano Rajoy, the Spanish prime minister, said in a tweet that his “priority is to look after the wounded in Las Ramblas and help the security services in their work“.
A witness told Catalan television that a white van travelling at speed entered the walkway running down the centre of the avenue and mowed down pedestrians as it zigzagged along. “I saw people sent flying“, the person said.
In a photograph shown by public broadcaster RTVE, three people were lying on the ground injured. Other videos showed five people down and recorded people screaming as they fled the scene.
Las Ramblas is at the heart of Barcelona, one of the most popular tourist destinations in Europe, and would have been full of foreigners as well as locals.
Police cordoned off the wide street normally heaving with tourists in August, ordering stores and nearby Metro and train stations to close. They asked people to stay away from the area so as not to get in the way of emergency services.
“All of Europe stands with Barcelona. Our thoughts are with the victims and all affected by this cowardly attack on innocents,“ said Donald Tusk, president of the European Council, on Twitter.
“全体欧洲人与巴塞罗那肩并肩。我们心系此次针对无辜者的懦弱袭击的受害者和所有受到影响的人，“欧洲理事会(European Council)主席唐纳德•图斯克(Donald Tusk)在Twitter上表示。
Spain is the world’s most visited tourist destination after France and the US, and Barcelona is particularly popular in the summer. T
ourism accounts for about 13 per cent of all jobs in Spain and the number of visitors is up 12 per cent this year.
Donald Trump, US president, tweeted: “The United States condemns the terror attack in Barcelona, Spain, and will do whatever is necessary to help. Be tough & strong, we love you!“
The incident in Barcelona is similar to the attack in Nice in July last year, when a Tunisian national drove a lorry along the Promenade des Anglais, killing more than 80 people who had gathered to celebrate Bastille Day.
此次巴塞罗那恐袭事件与去年7月法国尼斯遭遇的恐袭相似，当时一个突尼斯人驾驶卡车冲撞“英国人散步大道“(Promenade des Anglais)，80多名正在庆祝巴士底日的人遇害。
In Spain’s worst terror attack, 192 people were killed in co-ordinated bomb attacks on four commuter trains arriving at Madrid’s Atocha station in 2004.