Jammu:A head constable was martyred while as a Deputy Superintendent of Police and assistant Sub Inspector of Police were injured in an ongoing encounter in Billwar area of Kathua district in Jammu and Kashmir. An official told that during intial firefight, a head constable was martyred also DySP operations Sukhbir Singh and an assistant sub-inspector of Police were injured. Both the injured were immediately evacuated to hospital for advanced treatment, where the condition of the DySP is said to be critical. The operation in the area was underway at 10.30 am.