Daredevil bull-runners were crushed in a pile-up in the Spanish city of Pamplona on Saturday during its famed San Fermin festival, with at least 21 people hospitalised, officials said.
Television pictures showed a pile of runners, in traditional white shirts and red neckerchiefs, blocking the entrance to a bullring, the end point of the frantic dash through the town's cobbled streets.
The pile-up blocked several of the animals from charging into the arena, with panicked runners scrambling over the heads of those in front of them and others trying to pull the fallen free.
Two of the beasts -- of the six bulls and the six steers that ran -- leapt over the pile, crushing runners under their hooves. The others were herded to the arena through a side passage.
Several people were also trampled under the bulls' hooves during the crowded 850-metre (930-yard) dash through the city's narrow streets, which took four minutes and 15 seconds.
It was the sixth day of the fiesta in this northern town, which draws festival-goers and daredevils from around the world for a week of drinking and perilous bull-runs.
Javier Sesma, a doctor from the emergency unit of the local Navarra Hospital, told reporters that 21 people were injured in the run and the pile-up overall.
These included a 19-year-old man from the Spanish town of Vitoria who was in serious condition with a chest injury, and an Irish man with a less severe injury, also to his chest.
The 19-year-old was "in an especially serious condition with a chest trauma causing breathing problems, and is requiring breathing apparatus," Sesma said. "He is in a stable but serious condition."
He added that a further two people were being treated for gore wounds.
Spanish media said it was the worst stampede in decades at the festival.
Live television pictures showed one man being carried away unconscious, his face bleeding.
The chaotic run nearly doubled the overall toll of those hospitalised in the previous six days of runs. The toll published by the Navarre region authorities had stood at 22 before Saturday's charge.
Each year, hundreds of other people are treated by medics and the Red Cross at the scene for light injuries without being hospitalised.
Saturday's run involved bulls from the Fuente Ymbron ranch in Cadiz.