On a day typically remembered for the devastating atomic attack on Nagasaki in 1945, nuclear-armed North Korea and U.S. President Donald Trump both unleashed an unprecedented verbal barrage, with Trump threatening the North with "fire and fury like the world has never seen" and the North's military claiming it is finalizing plans for attacking the U.S. territory of Guam.

The heated rhetoric came after Trump was asked about a report suggesting that Pyongyang had cleared one of the final hurdles to being able to strike the U.S. with a nuclear-tipped missile.

"North Korea best not make any more threats to the United States. They will be met with fire and fury like the world has never seen," Trump said Tuesday in remarks widely broadcast from his golf resort in Bedminster, New Jersey, as Japan marked the 72nd anniversary of the U.S. atomic bombing of Nagasaki.