RNA - The posters of the demonstrators said "Islam is peace!", "Not in our name," and other similar slogans, RIA Novosti reported.
On Thursday, a van plowed into a crowd of pedestrians on Las Ramblas street in Barcelona, killing 14 people and injuring more than 100 others, in what police said was an act of terrorism.
Hours after the incident, another vehicle attack took place in the coastal town of Cambrils, South of Barcelona, killing one and injuring five civilians as well as a police officer.
Daesh (ISIS or ISIL) terrorist group claimed responsibility for the attacks.
Earlier on Saturday, Spain's Interior Minister Juan Ignacio Zoido said that the terrorist cell that had perpetrated the terror attacks in Barcelona and Cambrils had been dismantled. Catalan Home Affairs Minister Joaquim Forn Chiariello, however, said that it was early to speak about the full elimination of the cell while there were still two or three individuals on the run.