Running of the Bulls 2013: Horrific scenes in Pamplona as 3 men are brutally gored An American, 20, was gored in the stomach - he is in a serious condition A 42-year-old Spaniard was left with arm injuries Most bloody attack was 31-year-old twice in the groin and once in the leg Another three people, including a 48-year-old American, injured in run An American tourist was gored by a bull on this morning along with two Spaniards on the bloodiest day of the famous Spanish Running of the Bulls festival so far this year. The 20-year-old American tourist was gored in the stomach and a 42-year-old Spaniard in the arm as they took part in a bull-run in Pamplona, where people race through the Spanish town's cobbled streets pursued by the animals. But the most terrifying moments occurred when a lone bull which had become separated from the pack attacked a second Spanish runner as he lay helpless on the ground after being mown down by the animal and tripping in front of it. Horrifying: Three people were gored today on the bloodiest day of the famous Spanish Running of the Bulls festival so far this year Menacing: The runner gets tossed in the air by an El Pilar fighting bull after getting gored on Estafeta street during the sixth running of the bull Trapped: The man is caught between the horns of an El Pilar fighting bull after being gored Desperate: The man tries to escape the bull as a steward gets out a stick to distract the angry animal Attack: The half-ton beast gored the 31-year-old twice in the groin and once in the leg Frantic: A runner pulls on the tail of the bull in an attempt to distract it and make it drop the mauled man Terror: Other runners tried to distract the animal by grabbing its tail and waving newspapers at it. But a friend was only able to drag him away after more than half a minute of terror Emergency: The injured man, from the eastern Spanish province of Castellon between Barcelona and Alicante, was undergoing an emergency operation this morning. His condition was described as 'serious' The half-ton beast gored the 31-year-old twice in the groin and once in the leg. Dramatic TV pictures showed him being lifted in the air on the animal's horns with his trousers round his ankles. Other runners tried to distract the animal by grabbing its tail and waving newspapers at it. But a friend was only able to drag him away after more than half a minute of terror. The injured man, from the eastern Spanish province of Castellon between Barcelona and Alicante, was undergoing an emergency operation this morning. His condition was described as 'serious.' Agony: A 20-year-old American was gored in the stomach and a 42-year-old Spaniard in the arm Vicious: A man winces in pain as he is gored by a bull - six people in total were taken to hospital after today's run, the sixth of eight Treatment: Red Cross personnel look after a runner or 'mozo' after being gored by a bull from Pilar ranch, during the sixth bullrun of Sanfermines Emergency: Red Cross personnel carry a runner on a stretcher to receive treatment after being gored Surgeons were also operating on the American gored in the stomach by another bull earlier along the half-mile run through the town of Pamplona in northern Spain. The government press office identified the American gored only by his initials - P.E. - and gave his age as 20. He and a second American, aged 48 and thought to have suffered head injuries, were also described as being in a 'serious' condition. Six people in total were taken to hospital after today's run, the sixth of eight. The gorings were the first of this year's festival, in which just 15 runners had been taken to hospital over the first five days. Tradition: Revelers from around the world arrive to Pamplona every year to take part on some of the eight days of the running of the bulls Annual event: Fifteen people have been killed at the annual festival, made famous by a 1926 Ernest Hemingway novel, since records began in 1911 Run: The event has become increasingly popular with foreigners, who join the locals by staying up all night drinking and partying before thousands compete in the 8am run Draw: Pamplona's population of 200,000 swells to around two million during the festival, the largest in Spain Aggression: An 'El Pilar' fighting bull charges against a reveler Count: Hospital authorities initially said four people were gored but the regional government revised that down to three Fail: The woman does not succeed as she runs ahead while the bull makes contact Sport: A young woman tries to outrun a bull at the close of the running-with-the-bulls in the old city of Pamplona Duration: Today's event lasted just under five minutes, roughly double the normal length. Longer runs normally occur when some of the bulls get separated from the pack and become disoriented and more dangerous The black bull which caused most panic Friday made several more attempts to charge people before he was eventually guided along the narrow streets to join the rest for the pack in the pen of the packed bull ring Legend: Ernest Hemingway popularized the week-long fiesta in his book The Sun Also Rises in 1926 Deaths: The fighting bulls used in the centuries-old fiesta can weigh up to at 1,380 pounds (625 kilograms) and have killed 15 people since record-keeping began in 1924 They included gas firm worker John Bennett, 44, from Wolverhampton, who suffered knee injuries on the first run on Sunday after being trampled on by other runners as he fell near the end of the course. Fifteen people have been killed at the annual festival, made famous by a 1926 Ernest Hemingway novel, since records began in 1911. Between 200 to 300 people are usually injured each year. The most recent death was in 2009 when 27-year-old Daniel Jimeno, from Madrid, was gored in the neck by a bull called Capuchino. The event has become increasingly popular with foreigners, who join the locals by staying up all night drinking and partying before thousands compete in the 8am run. Pamplona's population of 200,000 swells to around two million during the festival, the largest in Spain. After each morning run, the animals are killed in an afternoon bullfight. Around 3,500 thrill-seekers compete in the most popular weekend runs with 2,000 taking part during the week.