Homeland Security spokeswoman Jenna Gaminde has previously told the media that Guam residents would be immediately alarmed by sirens from the All-Hazards Alert Warning System located across the small Pacific island in case North Korea delivers its promise to strike Guam "within two weeks".
Guam is home to U.S. Naval Base Guam and the Andersen Air Force Base.
Many are irked by the endless commentary about US forces on Guam by cable news pundits and experts attempting to introduce USA viewers to the island.
After decades of living peacefully, Guam authorities are urging their citizens to be prepared for an "imminent" missile attack from North Korea after the rogue state threatened to unleash "enveloping fire" at the small island sitting 9,700km from the US mainland.
The U.S. and its allies, Mattis said, are capable of fending off an attack.
Here's a closer look at Guam and its role in the US and North Korea's ongoing war of words.
Tourists stroll along a road on the island of Guam, a U.S. Pacific Territory, Aug. 10, 2017.
"I don't see a military solution and I don't think it's called for", said German Chancellor Angela Merkel.
"North Korea has always threatened other countries". North Korea has been at odds with the United States since the US backed South Korea during the Korean War.
Some posters lament the lack of knowledge about Guam on the part of most US residents.
The U.S. took control of Guam in 1898, when Spanish authorities surrendered to the U.S. Navy. And at the southern end, there's the Naval Base Guam that hosts the Submarine Squadron Fifteen and the USS Frank Cable.
China, however, could be a stumbling block but only if the Philippines continues to press its claim to territories in the South China Sea that are also claimed by Beijing. Residents do not pay USA income taxes or vote in the general election for US president. Guam was also a refueling and transfer spot for military personnel heading to Southeast Asia.
Guam elected its first governor in 1970 and, since 1972, has had one nonvoting delegate in the U.S. House of Representatives.
"We need to have our own military options to overwhelm the North", the Korea Economic Daily said in an editorial earlier this week.
"Some people [say], 'We just want our peace, our island groove that we've always have.' There are other people who are just sick and exhausted of the threats from North Korea because there sure have been many over the years".
The official languages of Guam are English and Chamorro, which means 'noble.' It's a Malayo-Polynesian language that has incorporated Spanish words over time.
In August a year ago, the North's Foreign Ministry warned that all USA military bases in the Pacific including Guam would "face ruin in the face of all-out and substantial attack" by the North's military.
The last time Guam feared a North Korean attack, in 2013, tensions eventually simmered down because then US President Barack Obama's administration avoided a verbal war with North Korean leader Kim Jong Un, the newspaper said.
Guam is armed with the U.S. Army's defense system known as Terminal High Altitude Area Defense, or THAAD, which can intercept missiles.
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