Local authorities in Spain are reporting that a 39- year-old Irish national has been injured during the first day of the famous San Fermin festival.
It is understood that the man is in hospital, where his injuries are described as non life-threatening.
Three other runners, understood to be two Americans and one local Spanish man, were not so lucky, as they sustained more serious injuries during the race.
The San Fermin festival is a week-long celebration held in the Spanish town of Pamplona. Among other traditions, it includes the running of the bulls, where hundreds of people run ahead of a pack of rampaging bulls.
Many people are injured, and even killed, during the running. The last confirmed fatality happened in 2009.