Bulls gored three runners, including an American, and trampled several others during the running of the bulls Friday at this town's San Fermin festival (search). At least four other runners were treated for cuts and bruises.

Juan Vallbona Serra, one of hundreds of people sprinting just ahead of the animals, was struck by a bull, which then fell on him. As the 23-year-old from Sabadell, Spain, struggled free, two other bulls hit him in the back and side, lifting him into the air.

His worst injury was a 6-inch gash in his right thigh, said Begona Lopez, a spokeswoman for Pamplona City Hall (search).

Two other runners were gored, including a 22-year-old man from Louisiana injured in the left elbow, the Spanish news agency Efe reported. Neither runner was identified.

All along the 900-yard route, which runs along narrow cobblestone streets from a corral to a bullring, runners in the popular festival were knocked off their feet, pushed against the thick wooden barricades lining the streets or trampled.

No one had been gored or otherwise seriously hurt in the first two days of the festival honoring Pamplona's patron saint but Friday's run was different from the start.

The bulls, including one weighing 1,300 pounds, charged out of the corral faster than usual, each going off on its own rather than all lumbering along as a pack.

Most of the approximately one dozen bulls — some bred for fighting, some docile — tried to avoid hitting the runners. The animals appeared to concentrate on staying upright as their hooves clattered along the uneven, slippery cobblestone.

At one right-hand corner, three piled up, labored heavily to their feet and continued.

Most bulls made it to the bullring about two and a half minutes after the start of the run. But two had to be coaxed into the ring and the run didn't officially end until about four minutes after the beasts charged out of the corral.

Since record-keeping began in 1924, 13 people have been killed at the festival. The last fatality was an American killed in 1995.