Suspected terrorists wearing Army uniforms opened fire at a bus and attacked a police station in Gurdaspur district early today leaving at least seven persons injured.The assailants came in a car and they first opened fire at a moving bus which was coming to Punjab side from Jammu and Kashmir on the Amaritsar-Pathankot highway. Four passengers were injured in it, who have been hospitalised, SSP Gurdaspur Gurpreet Singh said.