TOKYO, July 27 (Xinhua) -- A window fell off a U.S. military helicopter Friday morning at a U.S. base near Tokyo and no one was injured, Japanese Defense Minister Itsunori Onodera said.

The window fell right after the helicopter took off from the Atsugi base in Kanagawa prefecture, Onodera told reporters.

It's not clear yet which type of the helicopter it was and the defense ministry has asked the U.S. military to provide more information and prevent similar incidents from happening again, said Onodera.

A similar incident happened in Okinawa last December, as a window fell off a U.S. military CH-53E transport helicopter when it was flying over an elementary school near a U.S. base in the southernmost prefecture.

Though the incident caused no injuries, it added fuel to the anti-U.S. base sentiment of local residents in Okinawa as they complain about sufferings caused by aircraft noise, crimes committed by U.S. servicemen as well as safety concerns.