LONDON, June 20 (Reuters) - Lockheed Martin has raised concerns with the U.S. Defense Department and Federal Trade Commission about L3Harris's acquisition of Aerojet Rocketdyne, Lockheed's Chief Operating Officer Frank St. John said on Tuesday.

St. John said Lockheed, Aerojet's biggest customer, wanted L3Harris to ensure access to rocket motors, fair pricing and IP protections, adding it had received "little response" from L3Harris over its concerns.

L3Harris said in December it would buy Aerojet Rocketdyne for $4.7 billion in cash as it looks to tap into rising demand for missiles amid the Ukraine conflict. (Reporting by Valerie Insinna Editing by Mark Potter)