Separatist guerrillas on Monday shot at and critically wounded a police officer in Baramulla district in north Kashmir.A senior police officer told IANS here: "Two militants boarded a passenger bus at Mujgund on the Srinagar-Muzaffarabad road."They fired two pistol shots from close range in the moving bus at sub-inspector Gulam Mustafa of IRP 3rd battalion."They then hijacked the bus up to Shellu (Sopore) where they alighted and escaped."The police officer who sustained critical bullet injuries has been admitted to hospital in Srinagar for treatment.