The note also asks Guam's residents to "take time to talk" to family members or co-workers who might be troubled after North Korea vowed to ignite an "enveloping fire" of test missiles near the island, which is a US territory.
Guam's Office of Civil Defense began disseminating fact sheets Friday to help residents prepare for a missile attack from North Korea.
The US is against North Korea's nuclear weapons but Pyongyang says it will not give up on its nuclear deterrence unless Washington ends its hostile policy toward the country and dissolves the US-led United Nations command in South Korea.
"The Hwasong-12 rockets to be launched by the KPA (Korean People's Army) will cross the sky above Shimane, Hiroshima and Koichi Prefectures of Japan", the report said, citing General Kim Rak Gyom, commander of the Strategic Force of the KPA.
Pyongyang tested two intercontinental ballistic missiles last month.
Onodera did not elaborate whether he would actually order them to shoot down any of the missiles. "By making this advance notice, they are also sending a tacit message that what they are going to do is not an actual attack".
The government has chose to deploy Patriot interceptor missiles in parts of western Japan that North Korea's missiles are expected to fly over if Pyongyang actually goes through with its plan to fire them at Guam, Defense Ministry officials said Friday.
"Make sure you understand that this is not the final decision", Robert Carlin, the former chief of the Northeast Asia Division at the State Department's Bureau of Intelligence and Research, told reporters on a call organized by 38 North, a website that brings together experts on North Korea.
"They like to be unpredictable, they'll pop a missile off when no one is ready and they've done it quite a few times".
Over the past few days Donald Trump has issued a series of warnings and threats to North Korea, while the hermit state has hit back with plans to strike the USA territory of Guam. In July, North Korea made two test launches of ballistic missiles that provoked sharp reaction from the United States, Japan and South Korea. These launches, according to North Korea, are meant to contain United States forces in the Asia-Pacific region.
Pyongyang has repeatedly threatened to turn the South Korean capital, Seoul, into a "sea of fire" and has thousands of artillery units in place along the border to do it. Use of indiscreet and threatening language and actions should be restrained.
"They can not stop our advance".
As soon as the plan is developed, it will be referred to North Korea's leader Kim Jong-un who will kick off its implementation, if need be, KCNA noted.
U.S. Secretary of State Rex Tillerson recently said the U.S. was ready to hold dialogue with North Korea if the reclusive state puts an end to its provocations. The U.N. Security Council unanimously imposed new sanctions on North Korea on Saturday.
French President Emmanuel Macron called for the worldwide community to work with North Korea to "resume the path of dialogue without conditions", following a call with Trump Saturday.
Vladimir Putin's right-hand man Sergei Lavrov said the risk of a military conflict is very high and the succession of the threats issued by Washington and Pyongyang is deeply concerning.