YOKOSUKA NAVAL BASE, Japan — Two bomblike devices have been discovered here in the past nine months, according to the base’s Naval Criminal Investigative Service.

Both devices were ultimately determined to be hoaxes and contained no explosive residue, said a base NCIS agent, who requested anonymity due to the nature of his job.

"Looking at them, they did give the appearance of an explosive device," he said.

The discoveries took place in the Ships Repair Facility area of the base. The first was found in October near the waterfront and the second on April 21 near a fenced-in power transformer, the agent said.

The base’s explosive ordnance disposal team, the security department and military working dog teams were called to inspect the devices.

NCIS has reached out to the public for information, the agent said, by placing posters around the base asking people to report any information that might be pertinent.

NCIS officials said they are running the investigation but are working closely with law enforcement agencies.

"Even though the incident was a hoax, it’s a violation of a federal law, so it has to be taken seriously and investigated as if it was a real device," the agent said.

Base public affairs specialist Ben Avey said Commander Fleet Activities Yokosuka is supporting NCIS in its investigation but could not comment on the case because the investigation is ongoing.