The island is also home to a large USA military presence, a fact that has led to tension with some local residents, particularly those of the indigenous Chamorro community.
Here's a look at the US military's role on the island, which became a USA territory in 1898. Any order by the president could be executed quickly.
Calvo responded by saying he feels safe and confident with Trump's leadership: "I'm glad you're holding the helm, sir". Merkel declined to say whether Germany would stand with the U.S.in case of a military conflict with North Korea.
Merkel called on the U.N. Security Council to continue to address the issue.
"The powerful revolutionary Paektusan army of the DPRK, capable of fighting any war the USA wants, is now on the standby to launch fire into its mainland, waiting for an order of final attack", it said.
The five-minute drill begins with a siren on radio, and cars are stopped at designated spots.
Called Ulchi-Freedom Guardian, the exercises are expected to run August 21-31 and involve tens of thousands of American and South Korean troops on the ground and in the sea and air.
Conte criticises Chelsea players for loss of composure
Batshuayi, who scored the goal which clinched the league title last season, started ahead of new £70million signing Alvaro Morata. The champions had two men sent off in the game, Gary Cahill in the 14th minute and Cescc Fabregas in the 81st minute.
"(The North has) improved their missile launch capacity, but that's neither here nor there", he said.
Residents of the United States island of Guam say they're anxious but overall "unworried" amid missile threats from North Korea.
The heightened military activity on the peninsula this time is a concern because it could increase the possibility of a mishap or an overreaction of some sort by either side that could spin into a more serious escalation. North Korea claims the exercises are a rehearsal for war, but Washington and Seoul say they are necessary to deter North Korean aggression.
Along with the USA personnel on the island, there are about 7,100 of their family members as well as 6,700 civilian Defense Department workers and their dependents, according to Logan.
Chinese President Xi Jinping made a plea for cool-headedness over escalating tensions between the U.S. and North Korea in a phone conversation with U.S. President Donald Trump on Saturday, urging both sides to avoid words or actions that could worsen the situation.
"Make sure you understand that this is not the final decision", Robert Carlin, the former chief of the Northeast Asia Division at the State Department's Bureau of Intelligence and Research, told reporters on a call organized by 38 North, a website that brings together experts on North Korea.
Last week, New Zealand Prime Minister Bill English criticized Trump's "fire and fury" comments as "not helpful in an environment that's very tense". While already taking up 30 percent of the island, the American military has been seeking to increase its presence by relocating to Guam thousands of Marines who are now based in Okinawa, Japan.
North Korea's bold threat includes "several places they can stop or give up", Carlin said.