KUALA LUMPUR, Apr 17 (AP/UNB) - A Malaysia Airlines flight to London has been forced to return to Kuala Lumpur after one of its engines began experiencing trouble shortly after takeoff.

The airline says the captain of the Boeing 747-400 plane carrying 351 passengers and 21 crew members decided to turn back in the interest of passenger safety following a technical defect early Tuesday on one of the plane's four engines.

It said in a statement that the plane landed safely two hours later and was grounded upon arrival. Passengers were put on another plane to London eight hours later.

A spokesman said the airline is still investigating the source of the problem.

The plane uses U.S.-made Pratt & Whitney engines.