China has one of the most powerful militaries in the world.
Japan said Moscow had “big clout” with North Korea and asked Russia to cooperate.
North Korean missiles could use decoys and cooling shrouds to trick U.S. defense systems.
According to Reuters, "the number of sites that may ultimately be deployed had yet to be determined."
The drill in Japan took place two days after North Korea's latest missile launch.
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The U.S., Russia and China are all looking to surpass each other with military innovations such as missiles and drones that use artificial intelligence.
North Korea boasted that the ICBM it launched last week could carry a nuclear warhead.
Pyongyang is believed to be "four to five years" away from reaching the U.S. mainland, 5,700 miles away.
North Korea has tested several ballistic missiles that landed off Japan's coast this year.
The United States mainland is in the "sighting range for strike" said North Korea.
Analysts spotted three volleyball games apparently underway at the Punggye-Ri site.
China's foreign minister called on North Korea to halt nuclear activities and the U.S. to stop military drills.