According to the El País newspaper, two people opened fire on guests at a hotel before fleeing.
La Vanguardia reported the shooting took place at the Hotel Silken, near the intersection of La Rambla and Pinto Fortuny street.
Tweets from those on scene showed police outside the building.
El País reported one person was seriously injured, while another person had knife wounds.
Police have reportedly searched a nearby supermarket as the continue their manhunt.
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David Mack is a reporter and weekend editor for BuzzFeed News in New York.
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