A Spanish man was gored in the leg Monday as hundreds of thrill-seekers ran through the streets of Pamplona alongside six enormous bulls.

Meanwhile, a 31-year-old American man's condition deteriorated overnight while he was in intensive care after being left partially paralyzed in a side event Friday on the first day of the San Fermin festival, Pamplona spokeswoman Begona Lopez told The Associated Press.

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In the fourth of the festival's eight planned runs on Monday, six bulls charged along the 875-yard route leading to the bull ring in just over two minutes with only one incident where a leading bull caught a man.

Emergency services were called to the cobblestone streets after the bulls had run past.

A 32-year-old Pamplona native had to have surgery on his left thigh after being gored, Lopez said. Another 21-year-old man from Madrid was admitted to hospital with minor face injuries, she said.

The bulls belonged to the Cebada Gago stable, known for breeding some of the most dangerous bulls in the history of the festival, with 37 gorings in the last 20 years.

Since record-keeping began in 1924, 13 people have been killed during the runs. The last death was in 1995.

Five of the bulls stayed in a tight pack and ran through the narrow streets from a holding corral to the bull ring in the center of town in two minutes, two seconds. The last bull followed seven seconds later, but did not become disoriented, one of the greatest dangers during the runnings because stragglers can turn around and charge back the way they came, causing havoc among the tightly packed crowds running with the bulls.

The American's injuries were the festival's worst this year. He was thrown by one of five young cows set free in the Pamplona bull ring for people to taunt and dodge.

He has been identified as Ray Ducharme, a bond trader for Bank of America in Charlotte, North Carolina.

Lopez said that Ducharme's condition worsened since Sunday morning due to pulmonary complications, and that he was receiving assistance breathing.

In another incident linked to the festival, a bus carrying 23 Madrid resident home was hit by a drunk driver Sunday night, Lopez said. Seventeen people were injured in the crash, five of them critically.