LONDON (Reuters) - A holiday jet on its way from London‘s Gatwick airport to Jamaica made an unscheduled landing in the United States Sunday after fighting broke out among the passengers, an airline spokesman said. Twelve people, all British, were taken off the Boeing 767 plane at Norfolk, Virginia, David Parsons of the airline Airtours International told Sky television news in London. "We rather think it was some personal interplay between the people, who perhaps knew each other," he said. "Certainly they were fighting and uncontrollable, and clearly the calming techniques which we teach our cabin crews didn‘t work. Diversion was the only option." A spokesman for the Virginia airport said alcohol was a factor in the brawl. "About 12 passengers consumed quite a fair amount of alcohol and became somewhat unruly," airport spokesman Wayne Shank said. After questioning the passengers and flight crew, U.S. officials declined to press charges and the 12 unruly passengers were allowed to make arrangements for a return flight to London. The remainder of the passengers continued on to Jamaica. "I think the fact that the pilot put the airplane on the ground and allowed local police aboard was in and of itself a sobering experience," Shank said. In a separate incident, two men were arrested at London‘s Heathrow airport Sunday night after a stewardess on a Casablanca-to—London flight told police she had been groped. Police boarded the Royal Air Maroc Boeing 737 jet just after it landed to arrest the pair, who were later released after being given a formal warning for common assault. Police and airlines at Britain‘s third-busiest airport, in Manchester, northwest England, launched a new get tough campaign last week to fight the growing menace of "air rage" passengers who go berserk during flights. Airlines in Britain have reported a 400 percent increase in air rage incidents over the last three years and some fear that a berserk passenger will one day bring down a packed jet.