Six people have been injured on the first day of the bull running in Pamplona, reports Spanish El País.
During the controversial San Fermin festival, which lasts for about a week, bulls weighing up to 600 kilos are released in Pamplona's narrow alleys.
In front of them, hundreds of "participants" – mainly young men – run and try to avoid being gored.
Every year, dozens of people are injured in connection with the bull running. Since 1924, 16 people are said to have lost their lives after being speared by the animals.
The bulls that are sent out for the running are killed later the same day by bullfighters. Animal rights activists have long condemned the tradition as animal cruelty and torture.