Pyongyang raised the stakes just hours later -- saying it was considering missile strikes near US strategic military installations on Guam.
After US President Donald Trump threatened North Korea with "fire and fury" over its nuclear ambitions Tuesday, Pyongyang raised the stakes just hours later -- saying it was considering missile strikes near US strategic military installations on Guam.
In a televised address to the 162,000 residents on the Western Pacific island, Governor Eddie Calvo said Guam was working with Washington "to ensure our safety".
"I want to reassure the people of Guam that currently there is no threat to our island," he said.
George Charfauros, the territory's homeland security adviser, said there was "0.000001 percent chance of the North Korean missile hitting Guam".
His advice to residents to "relax and enjoy the paradise" appeared to hit home. There was no evidence of panic buying in stores Wednesday and gas stations were operating normally.
Shop worker Chelsea Nu told AFP the threat of attack was not even a conversation topic in her store.
"I haven't heard people talk about it. The customer traffic is normal. They're just buying school supplies because the school's just opened."
Guam, which advertises pristine beaches, clear blue skies and "world-famous sunsets" is a popular destination, with tourism a key pillar of its economy.
But it is also home to about 6,000 US troops and houses two US military installations -- the Andersen Air Force Base and the Naval Base Guam.
Despite the significant contribution the military makes to the local economy, there is a small but growing opposition to its presence.
Nationalists argue the territory is a potential target of aggression due to the presence of US forces.
But Calvo said it was the military which provided protection. "Those who are against the military will keep that distinction and make that argument. In the same manner, those who support the presence of the military on Guam will argue that this is what keeps us safe," he said.
Guam was described by President Barack Obama's defence secretary Ashton Carter as "an important strategic hub for the US military in the Western Pacific".
Calvo said there were "several levels of defence" strategically placed to protect Guam and he had been assured by the White House that a strike on the territory would be considered an attack on the United States.
"They have said that America will be defended. I also want to remind national media that Guam is American soil and we have 200,000 Americans in Guam and the Marianas. We are not just a military installation."
"With that said, I want to ensure that we are prepared for any eventuality."
Residents of Guam and the Marianas hold US citizenship.
On the streets of the capital Hagatna, there was a sense of calm.
"It's not like there's anything we can do, anyway. This is a small island. There's nowhere to run to," James Cruz told AFP.
Edith Tajalle was one of the few people to admit to being scared but added: "I know God will protect us."
Shopper Chuck Hambley believed "cooler heads will prevail" but said he was taking precautions just in case.
"I just have to make sure that my emergency kits are ready if Homeland Security says we should get ready. I am monitoring the situation."
Madeleine Bordallo, Guam's delegate to the US Congress, said North Korea's nuclear capabilities were "deeply troubling" but she was confident the island was safe and protected.
Guam, settled about 4,000 years ago by its indigenous Chamorros who now make up less than 40 percent of the population, was ceded by Spain to the United States in 1898.
It was captured and held for two and a half years by Japan during World War II before being retaken by US forces in 1944.
In 1950 Guam was recognised as a territory of the United States, granting its people US citizenship. But as it is not a state, the islanders cannot vote for the president and their congressional representative is a non-voting member.