A business class passenger on a Pakistan International Airlines (PIA) flight allegedly assaulted another while the plane was boarding in Lahore on Saturday, resulting in both being offloaded from the plane.

According to eyewitnesses and Airport Security Force (ASF) sources, a female passenger allegedly yelled at another near the entrance to the plane, then attacked her inside the plane.

Eyewitnesses described the attacker as a middle-aged woman, who gave her 20-something victim a "ruthless thrashing", tore her clothes and attacked her with glasses picked from a stewardess's trolley.

ASF sources said the victim, who is believed to be related to both the plane's pilot and her suspected attacker, had made towards the cockpit after being verbally abused, but was stopped by the attacker, who then allegedly scuffled with her.

According to eyewitnesses, the attacker's husband also witnessed the incident but did not intervene despite repeated requests from bystanders.

The scuffle caused the flight to be delayed by 35 minutes, the ASF sources told DawnNewsTV.

After reports of the incident began circulating on social media, PIA tweeted saying that the assaulter had been handed over to the ASF by the airline.

However, no charges were pressed against any individual involved in the incident, according to ASF sources.