President Donald Trump says the US military is “locked and loaded” to deal with North Korea, ramping up the rhetorical brinkmanship.
“Military solutions are now fully in place, locked and loaded, should North Korea act unwisely. Hopefully Kim Jong-un will find another path!” he tweeted.
He spoke as Pyongyang accused him of “driving” the Korean peninsula to the “brink of a nuclear war”.
North Korea has announced plans to fire missiles near the US territory of Guam.
The Pacific island’s homeland security agency issued a fact sheet on Friday with tips for residents to prepare for any missile threat.
It states: “Do not look at the flash or fireball – it can blind you.”
“Lie flat on the ground and cover your head. If the explosion is some distance away, it could take 30 seconds or more for the blast wave to hit.”
Moscow said the exchange of threats between Washington and Pyongyang “worry us very much”.
Foreign Minister Sergei Lavrov rated the risk of military conflict as “very high” as he put forward a joint Russian-Chinese plan to defuse the crisis.
German Chancellor Angela Merkel said there was no military solution, and “an escalation of the rhetoric is the wrong answer.”
Mr Trump’s tweet follows his threat earlier this week to rain “fire and fury” on Pyongyang.
His latest post came hours after his Defence Secretary Jim Mattis attempted to cool tensions by emphasising a peaceful resolution to the crisis.
Speaking in California late on Thursday, the Pentagon chief said it was his job to be ready for conflict.
But he said the effort by Secretary of State Rex Tillerson and UN Ambassador Nikki Haley “has diplomatic traction, it is gaining diplomatic results”.