Three men were gored and at least 10 others suffered cuts and bruises during a bull run in Pamplona.
It is the fourth day of Spain's renowned San Fermin Fiesta.
Mariano Lorente (27), of Pamplona, suffered a chest injury and two other local men were wounded in the shoulders and buttocks by the charging bulls, but none of the injuries appeared to be life-threatening.
As on the previous three days of the festival, six heavily muscled bulls raced through Pamplona's cobbled streets in a four-minute dash to the arena, where they would face bullfighters later in the afternoon.
One incident occurred when one runner slipped on the cobblestones and fell in front of the six bulls, but the man suffered only minor injuries.
More than one million people are expected to visit Pamplona during the festival. The runs, or "encierros," draw thousands of people testing their bravery and speed by running with the bulls.
AP