Defense Minister Itsunori Onodera urged caution on Friday as further provocation from North Korea is anticipated on Oct. 10, when the start of Lower House election coincides with one of the North's main anniversaries.
Tensions have risen on the Korean Peninsula since reclusive North Korea conducted its sixth and most powerful nuclear test on Sept. 3, leading to a new round of sanctions after a unanimous vote by the United Nations Security Council.
U.S. President Donald Trump has since traded insults with North Korean leaders, raising the stakes even further.