The Japan Coast Guard said Friday it scaled back its search for four Americans missing at sea after their yacht was lost in Typhoon Jangmi last week.

Searchers took the action because they believe the 66-foot yacht Jade Princess is no longer in the waters near the Okinawa prefectural island of Ishigaki, spokesman Masakazu Okuda said.

The decision to reduce search efforts came two days after the Japan Coast Guard said it believed the men were alive after possibly escaping the yacht in an inflatable raft.

Okuda declined to say Friday whether the men were still believed to be alive or when the search would end.

Searchers earlier found pieces of fiberglass and the yacht’s radio transmitter, which was discovered six hours after the Japan Coast Guard received a distress signal Sept. 28.

The four men who were aboard the yacht when it set sail from Malaysia Sept. 21 have not been identified.

Okuda said Japanese patrol ships will continue to be on the lookout, but searches by two rescue airplanes have been suspended.

A U.S. Navy P-3 Orion from Kadena Air Base on Okinawa continued to search the waters Friday.

U.S. Navy 7th Fleet spokesman Chief Petty Officer Robert Garnand said he did not know how long Navy efforts would continue.

The men departed from Malaysia with plans to stop on Okinawa before traveling on to Yokohama in mainland Japan.