PAMPLONA, July 10, 2008 (AFP) - The fourth day of the running of the bulls through Pamplona in northern Spain on Thursday left an American man briefly unconscious and six other people injured, including a Spanish man who was gored by a bull, organisers said.

The 31-year-old US citizen recovered consciousness in hospital where he is waiting for a brain scan while the 28-year-old Spaniard will need surgery after he was gored in the right thigh, they said in a statement.

The remaining five injured are Spaniards between the ages of 33 and 62. Three were hospitalized with concussions, one for bruises and another for a dislocated shoulder.

The bulls used in Thursday's run at the San Fermin festival, which wraps up on July 14, were especially big and fast.

They weighed more than 700 kilogrammes (1,500 pounds) and ran the 850-metre (935-yard) course from their corral to the bullring where they will face matadors in the afternoon in just two minutes and 41 seconds.

The running of the bulls take place at 8 a.m. (0600 GMT) on each day of the centuries-old festival which is also known for its all-night street parties that attract tourists from around the world.

Since 1911 fourteen people have been killed in the bull run, immortalized by Ernest Hemingway's 1926 novel 'The Sun Also Rises'.