Five people have been injured at the running of the bulls in Pamplona, Spain, with at least one gored by a bull's horns, medical officials said.
Red Cross spokesman Jose Aldaba said ambulances were taking the injured to a nearby hospital minutes after the race in the northern Spanish city began early on Saturday.
Rain before the race left the narrow cobbled streets more slippery than usual, and many runners were trampled while corralling the massive animals into Pamplona's bullring, as they completed the 930-yard course in just over two minutes.
Saturday's bulls each weighed between 1,100lb and 1,400lb.
The annual nine-day San Fermin festival was popularised by US novelist Ernest Hemingway.