AKIPRESS.COM - Part of a US helicopter has crashed on a school in Okinawa, Japan, renewing tensions with the local population, BBC reported.

The window dropped on the school grounds, slightly injuring one boy, news agency Kyodo said.

The southern island of Okinawa hosts the largest US military presence in Japan.

Over the past years, a number of accidents and crimes have led to growing local opposition to the US base.

According to the Reuters news agency, Japan's Chief Cabinet Secretary Yoshihide Suga said "this sort of incident creates anxiety not only among those involved with the school but the people of Okinawa and should never happen".

The US military confirmed in a statement that the window of one of its helicopters fell onto the sports ground of an elementary school outside the US Marine Corps Air Station Futenma.

"We take this report extremely seriously and are investigating the cause of this incident in close coordination with local authorities," the statement said. "This is a regrettable incident and we apologize for any anxiety it has caused the community."