A man accused of hijacking a Puerto Rico-bound flight to Cuba four decades ago has pleaded not guilty in a New York City courtroom.

Luis Armando Pena Soltren remained jailed Tuesday after a brief appearance before a federal magistrate judge in Manhattan.

Authorities say the U.S. citizen and his accomplices used weapons they hid in a diaper bag to hijack a Pan Am flight from Kennedy Airport to Puerto Rico in 1968.

The hijackers diverted the plane to Cuba. Pena Soltren has been in Cuba since. He was arrested Sunday after arriving in New York on a flight from Havana.

The FBI and federal prosecutors say the Cuban government authorized Pena Soltren's departure and was aware of his desire to return voluntarily.