The main accused in the case of attack on a woman constable on board a train in Ayodhya was gunned down, while two other accused were injured in an encounter with police on Friday, a senior official said.

Special Director General, law and order, Prashant Kumar told PTI, "Anish, the prime accused in the case of attack on a women constable on board the Saryu Express, was injured in an encounter with police in Pura Kalandar, Ayodhya. He later succumbed to injuries."

"His two other aides -- Azad and Vishambhar Dayal Dubey -- were also injured and are under arrest," the officer added.

The woman constable was found injured inside a compartment of the Saryu Express on August 30.

She was later admitted to a hospital in Lucknow where her condition is said to be stable.

A case was registered at the Government Railway Police (GRP) Ayodhya on the same day.

The Special Task Force (STF) along with local police and GRP were pressed in to identify and arrest the accused in the case after the Allahabad high court took suo motu cognisance of the incident.