A 10-year-old boy at a school in Okinawa was slightly injured when a transport helicopter from a nearby U.S. Marine Corps base lost a windshield as it flew overhead.

A statement from U.S. Forces, Japan, confirmed that a window from a CH-53E helicopter "fell onto the sports field of Daini Futenma Elementary School outside of Marine Corps Air Station Futenma. The aircraft immediately returned to MCAS Futenma and reported the incident."

Japan's Kyodo news agency says the 17-pound helicopter window and frame landed about 15 feet from the nearest child on what the news agency described as a "playground" and that the boy was hurt when gravel was thrown up by the impact.

"The safety of children should come first. It is unforgivable that it dropped in the middle of the playground," Okinawa Gov. Takeshi Onaga told reporters as he visited the site of Tuesday's crash, according to Kyodo.

The incident was likely to inflame further sentiment against the U.S. military bases at Okinawa, which locals have been pushing for some 20 years to have deactivated. The bases include not only Futenma, but Camp Hansen, also a Marine base, and Kadena Air Base.

In Tokyo, the news agency quoted Chief Cabinet Secretary Yoshihide Suga as saying the incident "stirred concern" among the people of the island prefecture. Defense Minister Itsunori Onodera said he wants the U.S. military to suspend flights of the same type of helicopter until safety is confirmed, Kyodo said.

Just last week, a part from another U.S. military helicopter fell from the sky onto a kindergarten roof, but no one was injured. In October, another CH-53 made an emergency landing on a farm, where it caught fire.

Last month, NPR's Elise Hu reported that a U.S. Marine stationed in Okinawa had drunkenly crashed his truck into another vehicle, killing the driver, a 61-year-old Japanese man.

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