Passengers onboard an international flight were left terrified after a portable phone charger exploded and burst into flames mid-air, sparking panic in the cabin and forcing an emergency landing.

The dramatic ordeal unravelled on a British Airways flight travelling from London to Las Vegas on Monday as the Boeing 787-9 Dreamliner approached its destination.

Chaos ensued when screams began to ring out when a portable phone charger being used to charge a device in the back pocket of a seat erupted into flames.

According to a witnesses, passengers heard a loud bang before smoke began to fill the cabin, triggering “pandemonium” from everyone onboard.

“The explosion, fire, then smell of smoke was terrifying. It was as if a bomb had gone off. People thought it might be a terrorist incident,” they told The Sun.

“The passenger charging their phone panicked when it began smouldering and threw the device over their head as it exploded in the air.

“The device was so hot it scorched the cabin floor where it landed. It was pandemonium onboard.”

Airline staff wasted no time jumping into action, with the source praising the crew’s swift response as they worked to extinguish the blaze.

“Crew acted brilliantly and put the fireball out with a Hafex extinguisher. It had melted part of the seat and the floor. Scorch marks were everywhere,” they said.

“It was a very scary experience. The issue of power banks must be addressed before one of the chargers blows a hole in the side of a plane.”

The publication reports air traffic control recordings captured the pilot informing authorities there had been a fire in the cabin and requesting assistance on arrival.

At one point, the pilot could be heard saying “We’re trying to keep the panic to a minimum.”

The source confirmed the pilot was not exaggerating the level of worry that had taken over the cabin.

“The pilot told air traffic controllers there was panic onboard, and he was not wrong,” they added.

Wild photos, obtained by The Sun, show the scorched interior left behind from the fiery explosion with the back of the seat and tray table scarred with soot.

Despite the touch-and-go scenario, British Airways confirmed the aircraft was able to land safely in Las Vegas.

The Nightly has contacted British Airways for comment.

“The safety of our customers and crew is the highest priority, the flight landed safely and customers disembarked normally,” the airline said in a statement to The Sun.

The frightening ordeal comes amid a rise in the number of problems related to power banks on aircrafts.

Last month the UK’s Civil Aviation Authority renewed warnings to passengers, urging them to “do the right thing” and take the rules seriously.

He said that there were “serious risks” of power banks overheating or catching fire mid-air if the rules are not followed.

Currently, power banks cannot be packed in checked luggage and need to be carried on board with passengers; however, incidents relating to portable chargers are on the up.

“It is absolutely a rule that can make a difference,” Jonathan Nicholson from the CAA told BBC News.

“I wouldn’t want to be the passenger who packed it in the wrong place and ended up with all the other passengers in the wrong city because the flight was diverted.”

He said that there were “serious risks” of power banks overheating or catching fire mid-air if the rules are not followed.