Two explosions were heard Thursday night near the U.S. Yokota base in western Tokyo, prompting police to set up a special investigative team.
The Metropolitan Police Department’s Public Security Bureau suspects that the incident was an attack by extremists, officials said Friday, though no damage to the base was confirmed.
The incident happened on a field near the base a little after 11:30 p.m. Nearby residents called the police, reporting what sounded like guns being fired.
Police officers discovered two steel pipes, with wire leads attached, in a field in the Nishisuna district in Tachikawa, about 500 meters southeast of the base. The police suspect that two projectiles were fired from the pipes, both of which were found pointing at the base.
In 2009, the police bureau searched locations related to a faction of Kakurokyo, an ultraleftist group, after a similar launch device was found near the base. On Thursday, the bureau arrested Shigeki Yamada, the faction’s 64-year-old leader, for staying in a hotel under a false name.