Lucknow,   Feb 1 : A policeman was shot dead Thursday by unidentified assailants in Uttar Pradesh's Mainpuri district in the parliamentary constituency of the ruling Samajwadi Party's chief Mulayam Singh Yadav, police said.

The incident took place when policeman Ajay Yadav was bringing back two murder accused Rishi Rajput and Chandan Kumar from court to prison, Superintendent of Police Shalabh Mathur told IANS.

The policeman was attacked by car-borne assailants near Bhogaon and the murder accused fled with the attackers, he said.

The two prison inmates were accused of killing a school principal and two others in 2011.