A U.S. military helicopter crash landed off the Japanese island of Okinawa on Wednesday, leaving seven people injured.The UH-60 Black Hawk performed a “hard-deck landing” on the USNS Red Cloud, the U.S. Pacific Command said. Aerial footage broadcast by NHK showed the chopper with part of its tail broken off.Of the 17 people on board, seven were injured and transported to a U.S. naval hospital on Okinawa, according to the U.S. Pacific Command.

It previously said six people were injured but then revised the figure.The incident happened at 1:46 p.m. (12:46 a.m. ET Wednesday) about 20 miles east of Okinawa. The helicopter was conducting a training mission at the time and the cause was under investigation, military officials said.

Japanese patrol boats and helicopters were initially sent to search for the helicopter and its crew.

However, Okinawa coast guard spokesman Yosuke Watanuki said it later received a call from U.S. Camp Foster military police, calling off the request for assistance.Okinawa, an island more than 900 miles southwest of Tokyo, is home to the bulk of U.S. military forces stationed in Japan.Seven Marines were killed in March after a Black Hawk crashed during a training exercise along the foggy Florida coast.