A Delta Air Lines flight from Barcelona to Boston was forced to make an emergency landing in Portugal on Sunday after smoke was detected in the cabin, impacting the travel plans of nearly 300 passengers.

The flight made the emergency landing in Porto, according to Fox News, and 14 passengers needed medical attention once the plane was safely on the ground. Four needed to be taken to the hospital for smoke inhalation but were only "lightly" affected.

A Delta spokesperson confirmed the incident to Fox News and said the diversion was due to a "reported mechanical issue." 

"The flight landed safely, and we apologize to our customers for the delay in their travels as we work to get them to Boston as safely and quickly as possible," the spokesperson said.

The Airbus carried 13 crew members and 283 customers. Delta said it is working to rebook the passengers as quickly as possible. 

The Federal Aviation Administration said air quality in the cabins is as "good as or better than the air found in offices and homes," but that "mechanical issues such as failures of an engine oil seal or recirculation fan bearings can cause fumes to enter the cabin."

When those mechanical issues occur, airlines are required to report the incidents to the FAA, which investigates the causes and ensures they’re fixed before the aircraft returns to service.

The incident comes after another Delta Air Line flight was forced to return to the Minneapolis/St. Paul International Airport earlier this month after its pilot experienced a medical issue on board the flight. The plane carried 178 passengers and seven crew members.

Misty Severi is a news reporter for Just The News. You can follow her on X for more coverage.