Running of the bulls in Pamplona leaves four people in hospital

A man who was gored and three others who were trampled in the first running of the bulls of this year's San Fermin festival have been hospitalised, officials in the Spanish city of Pamplona said.

Among those receiving medical treatment is a 20-year-old Canadian man with mild traumatic injuries, the officials from the Navarra regional government said in a statement.

The other men are of Spanish nationality and include a 38-year-old who was gored and a 40-year-old who sustained serious traumatic injuries.

Overnight rain had made the route's already-narrow cobbled streets more slippery than usual, adding to the danger in the traditional race.

Many runners were trampled early on, and others were also injured as the 12 animals entered Pamplona's bullring, but no information was available about the extent of their injuries.

The runners completed the 850m course, with bulls weighing 550-630 kilos each, in two minutes and 37 seconds.

The nine-day San Fermin fiesta was popularized by Nobel Literature laureate Ernest Hemingway.