The rear engine of an Eastern Airlines jumbo jet carrying 203 people exploded and disintegrated shortly after takeoff yesterday from Newark International Airport, federal authorities reported.

The Lockheed L1011 was forced to make an emergency landing at Kennedy International Airport about 35 minutes after takeoff. No one was injured.

Preliminary reports indicated that the rear portion of the L1011 suffered extensive damage and that the jet's controls may have been damaged.

"There is an indication the aft pressure bulkhead wall was penetrated at least once," a Federal Aviation Administration spokesman said. "Some oxygen masks dropped, but they didn't have any real pressurization problems. There also was possibly some damage to the control system, but they got down safely."

Eastern and Lockheed defended the engine, and Eastern officials said the explosion may not have been caused by an engine fault. "It could have been a bird flying into the engine, sloppy oil filling or something from the outside penetrating the engine. It's a good engine," an Eastern spokesman said.

But a National Transportation Safety Board spokesman said one of the Rolls-Royce engines failed on another Eastern flight May 25, forcing the jet to make a forced landing at Kennedy. That plane also landed safely.