Dispatch of U.S. aircraft to Japan may be signal A U.S. military aircraft that specializes in watching ballistic missiles arrived at a U.S. air base in Okinawa, Japan, on Tuesday, fueling speculation of an imminent North Korean weapons test.



According to Aircraft Spots, a Twitter account that tracks military aircraft worldwide, a U.S. Air Force RC-135U plane arrived at Kadena Air Base after departing from the headquarters of the U.S. Strategic Command at the Offutt Air Force Base in Nebraska.



Equipped with a telemetry radar that allows it to detect information about missiles several hundred kilometers away from a target, the Boeing RC-135U Combat Sent is a specialized reconnaissance plane used to locate and identify enemy military radar signals.



The U.S. Air Force has two Boeing RC-135Us in operation, both stationed at the Offutt Air Base.



The last time this type of plane was deployed to surveil the Korean Peninsula was on May 30, just weeks after North Korea tested several weapons that likely included short-range ballistic missiles similar to Russia’s Iskander missile system, known as the KN-23. The aircraft undertook a surveillance mission over the Yellow Sea, observing key missile test sites in North Korea like the launch pad at Tongchang-ri in North Pyongan Province.



Tuesday’s deployment of the RC-135U suggests Washington is keeping a close watch for another weapons test by Pyongyang. An RC-135U was also deployed around the Korean Peninsula in November 2017, when North Korea claimed it had successfully tested the Hwasong-15, an intercontinental ballistic missile supposedly capable of reaching the U.S. mainland.



Throughout this year, the North has conducted a total of 11 weapons tests, with the most recent on Oct. 3, when it was believed to have tested a submarine-launched ballistic missile.



Days later, on Oct. 6, Aircraft Spots detected the arrival of two U.S. E-8C Joint Stars surveillance aircraft at Kadena Air Base, planes that were used by the United States in the past to surveil North Korean missile activity.



The same day, the first denuclearization talks between the United States and North Korea in eight months ended fruitlessly in Stockholm, with Pyongyang’s top nuclear envoy Kim Myong-gil implying the country’s moratorium on nuclear and intercontinental ballistic missile tests would be reconsidered if Washington did not change its position in the negotiations.



“If the United States is not properly ready, who knows what horrible disasters can occur,” Kim told reporters the next day. “Let’s see what happens.”



The increased likelihood of another provocation from Pyongyang with the failure of talks prompted Washington to additionally deploy an RC-135S Cobra Ball to Okinawa, the same aircraft it used in March, July and August to observe North Korean military activities.



According to one South Korean military official, “the recent appearances of several of the United States’ main reconnaissance aircraft around the Korean Peninsula show that the United States has detected something unusual in North Korea.”



While there have been no overt signs of an imminent weapons test in the North in recent days, North Korean leader Kim Jong-un’s visits to locations outside of Pyongyang - like the Mount Kumgang tourism area and a hot springs resort in Yangdok County, South Pyongan Province - leaves open the possibility he may oversee another test as he did several times over the summer while apparently vacationing near Wonsan in Kangwon Province.



BY SHIM KYU-SEOK, LEE KEUN-PYUNG [shim.kyuseok@joongang.co.kr]