Three people have been gored during the fifth bull run at the Festival of San Fermín in Pamplona in Spain.
Warning: This story contains graphic images
Television images showed one bull repeatedly tossing and butting one runner against the wooden barriers on the edge of the ring on Monday.
The bull was then seen goring another in the back of the leg.
The Navarra regional government said a 25-year-old runner from Sunrise, Florida was gored in the calf in the bullring.
The other two people gored were Spaniards, one in the ring and one on the street.
None of them were seriously injured.
Three other runners, all Spaniards, were treated for injuries sustained in falls during the run.
It was the first run to involve injuries in the festival so far this year.
Eight people were gored when the festival was last held in 2019.
Sixteen people have died in Pamplona's bull runs since 1910, with the last death in 2009.
Monday's run lasted just over three minutes as hundreds of people, mostly men, ran ahead and alongside six fighting bulls as they charged through the cobblestone streets of the northern city.
There are three more daily runs before the festival ends on Thursday.
The runs finish at Pamplona's bullring, where later in the day the bulls are killed by professional bullfighters.
The Pamplona festival, which was featured in Ernest Hemingway's 1926 novel The Sun Also Rises, attracts tens of thousands of visitors.
The adrenaline rush of the morning bull run is followed by partying throughout the day and night.
AP/ABC