Residents of the tiny Pacific island of Guam say they're afraid of being caught in the middle of escalating tensions between the US and North Korea after Pyongyang announced it was examining plans for attacking the strategically important US territory.

Though local officials downplayed any threat, people who live and work on the island, which serves as a launching pad for the US military, said Wednesday they could no longer shrug off the idea of being a potential target.

"I'm a little worried, a little panicked. Is this really going to happen?" said Cecil Chugrad, a 37-year-old bus driver for a tour bus company in Guam. "If it's just me, I don't mind, but I have to worry about my son. I feel like moving [out of Guam] now."

Life in North Korea captured with a mobile phone Show all 30 1 /30 Life in North Korea captured with a mobile phone Life in North Korea captured with a mobile phone Farmer works in a field Getty Images Life in North Korea captured with a mobile phone Women soldier walk on the street Getty Images Life in North Korea captured with a mobile phone A female soldier guards railway Getty Images Life in North Korea captured with a mobile phone A general view of platform of Pyongyang Railway Station Getty Images Life in North Korea captured with a mobile phone Students stage a protest against South Korea and the US in Pyongyang Getty Images Life in North Korea captured with a mobile phone Students rehearsal for celebrating the 70th birthday of Workers' Party of Korea Getty Images Life in North Korea captured with a mobile phone People enjoy the cool at the carriage door Getty Images Life in North Korea captured with a mobile phone A general view of countryside Getty Images Life in North Korea captured with a mobile phone Korean People's Army soldier rest on the rail 2015 Getty Images Life in North Korea captured with a mobile phone A little boy begs food on the platform in Hamhung Railway Station in Hamhung 2015 Getty Images Life in North Korea captured with a mobile phone Children swim in a river in noon Getty Images Life in North Korea captured with a mobile phone People cross a railway crossing 2015 Getty Images Life in North Korea captured with a mobile phone A boy collects corn cob beside a railway Getty Images Life in North Korea captured with a mobile phone A customs officer is seen on the train No.100 from Moscow to Pyongyang at Tumangang railway station in Tumangang Getty Images Life in North Korea captured with a mobile phone A customs officer checks a passenger's mobile device on the train to Pyongyang Getty Images Life in North Korea captured with a mobile phone A railway station in Tumangang Getty Images Life in North Korea captured with a mobile phone A general view of the railway station in Tumangang Getty Images Life in North Korea captured with a mobile phone Kids pass by Tumanggang railway station in Tumanggang 2015 Getty Images Life in North Korea captured with a mobile phone A general view of Tumangang Getty Images Life in North Korea captured with a mobile phone A general view of Tumangang - a small town located at North Korea and Russia border Getty Images Life in North Korea captured with a mobile phone A train carriage on it's way to Pyongyang is delayed for a day and half due to military transportation in Tumangang Getty Images Life in North Korea captured with a mobile phone A customs officers talks to a passenger at Tumanggang railway station in Tumanggang Getty Images Life in North Korea captured with a mobile phone A little girl walks on the street in Tumanggang 2015 Getty Images Life in North Korea captured with a mobile phone An elderly man is seen in Tumangang Getty Images Life in North Korea captured with a mobile phone Kids go to school in morning in Tumangang 2015 Getty Images Life in North Korea captured with a mobile phone Life in North Korea captured with a mobile phone Life in North Korea captured with a mobile phone Life in North Korea captured with a mobile phone Life in North Korea captured with a mobile phone

Guam is used to threats from North Korea but advances in the country's nuclear programme, paired with fiery rhetoric from President Donald Trump, has raised the already high animosity and heightened worries that a miscalculation might spark conflict between the nuclear-armed nations.

Reports suggested North Korea mastered a technological hurdle needed to strike the US with a nuclear missile. The advances were detailed in an official Japanese assessment and later a Washington Post story that cited US intelligence officials and a confidential Defence Intelligence Agency report.

In response, Trump on Tuesday threatened the communist country "with fire and fury". On Wednesday, the North Korean army said in a statement that it was studying a plan to create an "enveloping fire" in areas around Guam with medium- to long-range ballistic missiles.

While it is extremely unlikely that Pyongyang would risk the assured annihilation of its revered leadership with a pre-emptive attack on US citizens, some residents are concerned.

"If anything happens, we've all got to be ready, be prepared, and pray to God that it doesn't happen," Daisy Mendiola, 56, said after finishing lunch with her family at a restaurant near Hagatna. "Everyone's afraid, because we're dealing with power that's beyond us."

Other residents are worried about the political atmosphere and the government's ability to find a peaceful solution.

Todd Thompson, a lawyer who lives on Guam, said he laughed off past threats because he "figured cooler heads in Washington would prevail, and it was just an idle threat".

"But I have to say, I'm not laughing now," Thompson said. "My concern is that things have changed in Washington, and who knows what's going to happen?"

His brother, Mitch Thompson, who also lives on Guam, added he believes "a lot of people have no confidence that the White House will do the right thing under the circumstances".

However, the brothers say they haven't seen anyone panicking or stocking up on supplies.

"I think people are just stunned and really don't know what to think," Todd Thompson said.

Guam is about 2,100 miles (3,380 kilometers) southeast of Pyongyang and 3,800 miles (6,115 kilometers) west of Honolulu in the Pacific Ocean. For years, North Korea has claimed Guam is within its missiles' striking distance, making furious statements each time when the US flew powerful bombers from the island's air base to the Korean Peninsula.

In August last year, the North's Foreign Ministry warned that all US military bases in the Pacific including Guam would "face ruin in the face of all-out and substantial attack" by the North's military. In the spring of 2013, state media cited leader Kim Jong Un as having ordered his military to prepare plans on launching strikes on US military bases in Guam, Hawaii and South Korea as well as the American mainland.

Guam is armed with the US Army's defence system known as Terminal High Altitude Area Defence, or THAAD, which can intercept missiles.

Similar threats in 2013 led Guam's US Congresswoman Madeleine Z Bordallo to advocate for the THAAD system, she said in a statement Wednesday.

"North Korea's most recent threat to target Guam is dangerous and it further heightens tensions in our region," Bordallo said. "While we have heard threats like this in the past, I take them very seriously."

Guam's Homeland Security Advisor George Charfauros urged calm and said defences are in place for such threats.

"An attack or threat to Guam is a threat or attack on the United States," said Guam Governor Eddie Calvo, who said he spoke with White House officials Monday morning. "They have said that America will be defended."

A travel agent on Guam said they haven't had a surge of customers seeking to book flights off the island.

"It's not bad at all, no chaos," said Mariah Sablan, who works for Golden Dragon Travel Inc. "It's just like a regular business day."