Washington DC - Freight carriers UPS and FedEx said they have grounded their fleets of MD-11 cargo planes, after one of them was involved in a deadly crash in Kentucky this week.

A McDonnell Douglas MD-11 aircraft operated by UPS exploded into flames when it crashed shortly after departing on Tuesday from the airport in the US city of Louisville, killing at least 14 people. A three-person crew was aboard.

"Out of an abundance of caution and in the interest of safety, we have made the decision to temporarily ground our MD-11 fleet," UPS said Friday.

"The grounding is effective immediately. We made this decision proactively at the recommendation of the aircraft manufacturer," the courier added.

Accidents Investigators reveal cause of Kentucky cargo plane crash as death toll rises

It said around 9% of UPS's fleet are MD-11s.

FedEx said Saturday it, too, had grounded its 28 MD-11s out of a total fleet of around 700 aircraft as it conducts a safety review.

The carrier is implementing a contingency plan to minimize disruptions, the company said in a statement.

Kentucky Governor Andy Beshear said another crash victim had been located, bringing the total number to 14.

"Please pray for these families, the Louisville community, and everyone affected by this terrible event," he said on X.

The plane, filled with around 38,000 gallons of fuel for the long-haul flight to Hawaii, narrowly missed a major Ford vehicle assembly plant that employs about 3,000 people.

Aerial footage of the crash site showed a long trail of debris as firefighters poured water on the flames, with smoke billowing from the area.

Investigators have said the accident was caused by one of the engines catching fire and detaching during takeoff.

Accidents Death toll rises after UPS cargo plane crashes near Louisville airport in fiery scene

Todd Inman, a member of the National Transportation Safety Board, said this week that investigators had identified the flight data recorder and cockpit voice recorder – known as a plane's black boxes – and would send them to Washington for analysis.

The crash was reportedly the deadliest in UPS history. Its main hub, Worldport, is in Louisville, where it employs thousands of people.

According to the NTSB, the plane was built in 1991 and was modified into a cargo aircraft. McDonnell Douglas merged with Boeing in 1997.

The crash comes amid the longest government shutdown in US history, with Transportation Secretary Sean Duffy warning this week of "mass chaos" in the skies due to a lack of air traffic control staff.

Inman said the NTSB was not aware of any staff shortages at Louisville's airport at the time of the crash.