WASHINGTON (AFP) - The body of an adolescent boy was found in a wheel well of a US military cargo plane after the aircraft landed in Germany over the weekend, the Pentagon said on Tuesday.

The "apparent stowaway" was discovered Sunday night during a "routine post-flight inspection" of the C-130J aircraft at Ramstein Air Base, spokesman Rear Admiral John Kirby told a news conference.

The boy was found above the aircraft's rear landing gear and it was unclear when or where he had climbed into the compartment, Adm Kirby said. The boy "was an adolescent black male, possibly of African origin," he said.

The plane had been flying operations in support of US Africa Command "with stops in a few countries," said Adm Kirby, without naming the nations.

A US defence official, who spoke on condition of anonymity, said the plane had been on an eight-day mission in Africa that included a visit to Mali. German authorities were conducting an autopsy and an investigation into the case.