<sod >They started flocking into the building.< eod>< sod > ' Greg Bird told MailOnline he was sat outside a coffee shop near Oxford Circus station when he saw 'about 50 people sprinting around the corner and screaming'.  About 90 minutes after responding police said there was no evidence of any shots, casualties or suspects and stood down the operation just after 6pm. A large section of Oxford Street was locked down at the height of the scare, but Oxford Circus and Bond Street stations later reopened. Cordons have been removed and the area has returned to normal. British Transport Police confirmed the mass evacuation was caused by an 'altercation' between two men and urged those pictured in the CCTV images to come forward.< eod>