Ahead of their La Liga opener against Real Betis on Friday, Barcelona's players and coaching staff held a minute of silence following Thursday's terror attacks in the city.
A total of 14 people have been killed and over a hundred injured after two incidents took place on the same day.
The country, as well as its biggest football stars, were left mourning in the wake of tragedy.
Barca had already confirmed that players of all their teams would wear black armbands during games this weekend, while a minute's silence will be held at matches across Spain.
The Real Madrid squad formed a circle at their training ground for a minute's silence as a mark of respect for the victims/Twitter
The Real Madrid squad formed a circle at their training ground for a minute's silence as a mark of respect for the victims/Twitter
Other Spanish clubs held tributes of their own before training on Friday, with Real Madrid following suit by forming a circle for a minute's silence ahead of their final preparations for their league opener away to Deportivo.
Barcelona said in a statement: "FC Barcelona wants to express its profound sorrow and utter disgust at the terrorist attack that has hit the heart of our city, la Rambla de Barcelona. The club wishes to send our support and thoughts to the victims, their families and friends as well as the people of Barcelona and its visitors.
"As a mark of respect, the flags will fly at half-mast at the club's installations and the players from both teams will wear black armbands in all matches this weekend. On Sunday, before the 2017-18 La Liga opener against Betis, the Nou Camp will hold a minute's silence in recognition and memory of the victims."