American and Japanese authorities on Friday were still trying to determine the source of two small explosions that hit just outside the U.S. air base near Tokyo.
The blasts occurred late Thursday, CNN reported. So far, investigators have discovered two metal tubes and a low-tech timing device — and they’ve deemed it an “improvised launch device.”
CNN reported that nobody was injured.
“We can confirm there was an improvised launch device outside Yokota [Air Base] over the evening,” a statement from the base read. “We take matters of security at our installation very seriously, and we are assisting the Japanese National Police in their investigation into the matter.”
U.S. officials searched the base overnight for suspects. Meanwhile, Capt. Ray Geoffroy, a spokesman for the Air Force, said they’re also looking for any possible impact points, CNN said.