A United States Navy plane carrying 11 people crashed into the Pacific Ocean off Japan on 22 November.
The Washington Post quoted the US Navy's 7th Fleet, as saying, that eight people were found and the search for remaining three was underway.
However, it was not clear whether the people found were dead or alive.
The C-2 Greyhound aircraft was travelling to the USS Ronald Reagan aircraft carrier, which is currently operating in the Philippine Sea.
The ship had participated in Annual Exercise 2017 (AE17), a bilateral field-training exercise with the Japanese Navy conducted in waters off Japan.
Japanese Minister of Defence Itsunori Onodera told reporters in Tokyo that the accident occured due to the engine malfuntion.
"The Maritime Self-Defense Force is currently searching with US forces," Onodera said, according to public broadcaster NHK.
He added, "We received information from U.S. Forces that the cause is possibly engine malfunction."
The accident is the latest in a series of disasters in 2017 for the 7th Fleet, including two collisions involving guided-missile destroyers that left 17 sailors dead.