Around 15 people clashed in Fittja, in the south of Stockholm, in a huge fight broken up by police.  Officers found an AK47 assault rifle on a footbridge near the brawl.  Local media say police shut down the metro station to passengers and stopped trains running through the station as they patrolled the area. It is thought two men and a gang of 15 youngsters were at the centre of the fighting.  One witness told Aftonbladet the mob chased away two men before the duo came back armed with a gun.  Towe Hägg, from Stockholm Police, said the force has launched an investigation. Is is unclear if anyone was injured in the clash that took place at around 7.40pm local time. Last Friday another brawl broke out in central Sweden at Hallsberg Alléskolan. Police have arrested a number of people have started…