A British Airways flight from London’s Heathrow Airport to Valencia, Spain, was forced to evacuate all passengers on Monday afternoon as the cabin filled with smoke during its arrival.

In a statement, British Airways said that the flight had experienced a “technical issue on its landing approach.”

The air carrier said that three customers were taken to a hospital after the incident as a precaution and had subsequently been discharged.

The aircraft involved in the incident was an Airbus A321, carrying 175 passengers, six cabin crew and two pilots, British Airways said.

Gayle Fitzpatrick, one passenger on the flight, wrote on Twitter that the passengers had been forced to disembark via emergency chutes after it landed.

The landing “felt like a horror film,” passenger Lucy Brown wrote on Twitter, adding that she was thankful everyone was safe.

“PANIC!!! FEAR — have never been through anything like that before,” Dani Meroño Bori, a Spanish sports journalist tweeted.

British Airways has not disclosed what caused smoke to fill the cabin during the last 10 minutes of Flight BA422.

However, El Pais reported Tuesday that the landing took place after a fire was detected in one of the plane’s engines. Citing a regional emergency center, the Spanish newspaper reported that the pilot told the control tower “engine on fire,” but when firefighters arrived after the landing, they found only smoke.

On social media and in interviews with media outlets, a number of passengers complained that the handling of the incident by British Airways staff had appeared uncoordinated and chaotic, with long waits to get luggage and little communication from staff.

In a statement, British Airways said that “the safety of our customers and crew is always our highest priority.”

“In addition to our team on site, other British Airways team members have arrived in Valencia to help our customers and our local airport partners with anything they need,” the statement continued.

Brown said she was grateful for the British Airways team that had been sent in to help from Madrid.

“Hopefully we’ll find out what went wrong on the plane soon so it never happens again,” she wrote.