(Reuters) -Lockheed Martin Corp's Sikorsky unit on Wednesday sought a review of the U.S. Army's decision to award a contract for its next-generation helicopter to Textron Inc's Bell unit.

The company, which filed its protest with the U.S. Government Accountability Office (GAO), said it had partner Boeing Co's support.

Earlier this month, the Army ended a years-long competition aimed at finding a replacement for the Black Hawk utility helicopter after it assigned the contract to Textron's unit.

The contract is potentially worth around $70 billion - over decades - depending on how many are ordered, according to the Army, which is looking to retire more than 2,000 medium-class UH-60 Black Hawk utility helicopters built by Sikorsky since the 1970s.

The filing of a protest by Lockheed and Boeing triggers a formal legal review from the GAO and requires a decision within 100 days, the agency said.

The Army acknowledges Sikorsky's decision to file for protest and will comply with GAO's requirements, said a spokesperson for U.S. Army Program Executive Office - Aviation.

The Pentagon did not respond to a request for comment.

(Reporting by Priyamvada C in Bengaluru; Editing by Anil D'Silva)