BRUSSELS -- European leaders on Thursday expressed condolences following the terrorist attack in Barcelona.

"This cowardly attack has deliberately targeted those enjoying life and sharing time with family and friends. We will never be cowed by such barbarism," European Commission President Jean-Claude Juncker said in a statement.

"I send my deepest condolences to the families and loved ones of the victims, as well as to Prime Minister Rajoy and the people of Spain. My thoughts are with the people of Barcelona," he said.

Juncker added the Commission is "at the full disposal of the authorities for any help or assistance".

Echoing Juncker, European Council President Donald Tusk tweeted: "All of Europe stands with Barcelona. Our thoughts are with the victims and all affected by this cowardly attack on innocents."

European Parliament President Antonio Tajani said: "My heart goes out to the victims of the attack in Barcelona and their families. Full support to authorities. EU united in defense of peace."

British Prime Minister Theresa May said on Twitter that her thoughts were with the victims, adding that "the UK stands with Spain against terror".

French President Emmanuel Macron tweeted: "All my thoughts and the solidarity of France are with the victims of the tragic attack in Barcelona," adding that "we remain united and determined."

Greek Prime Minister Alexis Tsipras expressed Greece's solidarity with the Spanish people and the country's sympathy for the families of the victims.

"In these difficult moments, all our thoughts and our solidarity are with the Spanish people. We express our support to the families of the victims," he tweeted.

Danish Prime Minister Lars Loekke Rasmussen expressed his shock over the attack in which two Danes were confirmed injured.

"My thoughts are with the victims in Barcelona and their loved ones," Rasmussen said on his Twitter account, noting that he was shocked to learn about "another evil attack in Europe".

Finnish President Sauli Niinisto said on his Twitter that "terrorists have again targeted Europe". He said he was following the situation with extreme seriousness.

Thirteen people were killed and over 100 others were injured after a van rammed into a crowd in Barcelona's city center on Thursday afternoon, according to Spanish officials. (Xinhua)