With tensions escalating over North Korea's continued nuclear and ballistic missile testing in a bid to give it the ability to target the United States with a powerful, nuclear-tipped missile, Trump has warned of US military action.
The relocation came after a North Korean missile was test-fired last week and flew over southern Hokkaido and landed in the Pacific off the island's east coast - the second flyover in less than a month.
Japan already deployed another PAC-3 system to another part of the island.
The bottom line, he said, is that if the missiles were a threat to Guam or Japan, "that would elicit a different response from us".
"Based on North Korea's demonstrated science and technological capabilities - coupled with the priority Pyongyang places on missile programs - North Korea probably is capable of producing UDMH domestically", Timothy Barrett, a spokesman for the director of national intelligence, told the Times.
The U.S.is deciding whether a ballistic missile fired by North Korea is enough of a threat to bring it down even if its trajectory doesn't include the U.S. or its allies, according to CNN.
Since January, North Korea has tested five ballistic missiles and a nuclear weapon, and reporters asked Mattis why the United States doesn't shoot the missiles down.
The secretary made a September 15 trip to Mexico City to strengthen the bilateral defense relationship and participate in Mexican Independence Day activities, and to the reporters he said that Mexico had declared the North Korean ambassador a persona non grata. It also has threatened to launch missiles close to the coast of Guam, a US island territory in the Pacific. South Korea carried out a drill called "live fire drill" that if a missile launched from North Korea, South Korea could hit Sunan airport, which is the biggest military launch site in North Korea.
The AP reporting the Japanese government deployed a mobile missile-defense system on September 19 on the northern island of Hokkaido.
It comes as United Nations Secretary-General Antonio Guterres appealed for war with North Korea to be avoided and criticised world leaders stoking resentment over refugees for political gain, two apparent digs at President Donald Trump.
"This is the time for statesmanship", said the former prime minister of Portugal. "We must be willing to be persuaded by them".