A pack of fighting bulls gored a Spaniard, knocked an American unconscious and injured five other people Thursday in a dash through the streets of Pamplona to the city bullring, officials said.

This year's fourth run through the streets of Pamplona in the annual San Fermin Festival was relatively fast and featured bulls weighing up to 1,540 pounds, which is about as big as fighting bulls can get.

Early in the course one runner apparently just stopped and turned around to face the animals, and was bowled over violently by one of them.

His decision was perhaps the worst thing you can do at the festival, where the cardinal rule for runners is to keep moving, or, in a pinch, hit the ground face-down and stay there until the pack has moved on.

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The Navarra regional government said a 31-year-old American was hospitalized, unconscious with a severe head injury, but that he later regained consciousness and was to undergo tests. His name and home town were not released.

It was not immediately clear if he was the man who stopped in mid-run.

A 28-year-old Spaniard was gored in the right thigh and will have to undergo surgery, the government said.

The runs to the city bullring take place at 8 a.m. daily and are the highlight of a centuries-old festival that became world famous with Ernest Hemingway's 1926 novel "The Sun Also Rises."

Professional matadors fight, and invariably kill, the bulls each afternoon of the festival.

Fourteen runners have died in the running of the bulls since record-keeping began in 1924.

The last fatality from a goring was a 22-year-old American, Matthew Tassio, in 1995. In 2003, a 63-year-old Pamplona native, Fermin Etxeberri, was trampled in the head by a bull and died after spending several months in a coma.

In Wednesday's run an American from California was gored in the buttocks and had to undergo surgery.

On Sunday, a 23-year-old Irishman died after falling from an ancient wall that encircles the old quarter of Pamplona.