U.S. aviation regulators are drafting enhanced inspection mandates to step up their examinations of more than 600 Boeing Co's 757 airplanes worldwide, the Wall Street Journal reported, citing people familiar with the matter.

Imminent safety directives by the Federal Aviation Administration (FAA) are expected to cover certain older models of the widely-used twin-engine planes, the paper said.

We had asked for the inspection. The FAA has mandated to ensure that those inspections are undertaken by the operators, Boeing media officer Liz Verdier told Reuters.

These airplanes are older airplanes. It's all part of the system to keep the airplanes safe. It's for the U.S. but it does tend to be picked up by other world regulators and enacted, Verdier added.

FAA could not be immediately reached for comment by Reuters outside regular U.S. business hours.

Regulators in Europe and other regions are expected to follow the FAA's lead, affecting many more planes, the Journal said.

(Reporting by Abhinav Sharma in Bangalore; Editing by Lincoln Feast)