Shoppers and staff were forced to flee after a fire erupted inside a shopping mall in Bangkok, Thailand.The blaze - reportedly caused by a Christmas tree that went up in flames under an escalator - happened inside the Central World building in the heart of the Thai capital.Footage shows the fire raging, while thick clouds of grey smoke were also seen inside the mall.The inferno started when an electrical short circuit ignited a Christmas tree under an escalator on the seventh floor of the building.