The White House has said that the US is "fully capable" of defending itself against a North Korean ballistic missile attack.
Asked whether North Korea's threat was being taken seriously, a White House spokeswoman said that foreign government's must be "taken at their word".
More top news
The major party leaders' campaigns for the General Election will remain suspended on Wednesday following the Manchester terror attack.
Thousands of people have donated to help the families of the victims - as well as a homeless man who came to their aid.
Some children, particularly those who have been more directly affected, may show symptoms of stress and trauma.