Supporters of Pakistan Tehrik-e-Insaf during a rally in Peshawar. File / AFP

A father killed his son after the pair disagreed about which political party flag to display in the lead-up to Pakistan's general election, police said.

The argument broke out when the son, Atta-ur Rehman, who recently returned from working in a foreign country, hoisted the flag of former prime minister Imran Khan's Pakistan Tehrik-e-Insaf (PTI) party at the family home on the outskirts of Peshawar in Khyber Pakhtunkhwa province.

"The father, Atta-ur Rehman, prohibited his son, Att-ur Rehman, from hoisting the PTI flag at home, but the son refused to take it down and abandon PTI," said district police official Naseer Farid.

"The argument escalated, and in a fit of anger, the father fired a pistol at his 31-year-old son, before fleeing the house." The son died on the way to the hospital.

Police are searching for the father, who was affiliated with the nationalist Awami National Party and had previously displayed their flag.

The incident has sent shockwaves through the community, highlighting the dangerous consequences of political polarisation within families, they added.

The father, following the fatal shooting, managed to flee the scene before the law enforcement could apprehend him. The Peshawar police have initiated an investigation into the matter, with the motive identified as a political dispute within the family.

Elections which are scheduled for February 8 are often marred with violence in Pakistan, with candidates targeted by Islamist bombings and gun attacks.

In the first week of February some 5,000 paramilitary Frontier Constabulary (FC) forces will deploy to the northwestern Khyber Pakhtunkhwa province bordering Afghanistan, commander Moazzam Jah Ansari told AFP.

Agence France-Presse