Guam Homeland Security is calling on residents to stay calm amid reports North Korea is examining a plan to strike the territory.
A spokesman for the Korean People's Army said once the North Korean leader Kim Jong Un had made a decision the strike plan would be "put into practice in a multi-current and consecutive way any moment".
The comments came in a statement from the Korean People's Army carried by the North's state-run KCNA news agency just hours after the United States President Donald Trump told the North that any threat to the US would be met with "fire and fury".
KCNA said its military was "carefully examining the operational plan for making an enveloping fire at the areas around Guam with medium-to-long-range strategic ballistic rocket Hwasong-12".
However, a spokesperson from Guam's Homeland Security office, Jenna Gaminde, said while the situation was concerning, there had been no heightening of security in the US territory.
"Our homeland security advisor has gone on record to let the public know that we continue to place our confidence in the US Department of Defense. There are multiple layers of defence across the waves, through South Korea, the Sea of Japan from Japan, even before it gets to our area here on Guam. So we place our confidence on our military partners."
Guam is a US territory which hosts major American airforce and naval bases, and a Terminal High Altitude Area Defense or THAAD, anti-missile system.