SEOUL, South Korea — Until recently, the world considered North Korealargely a menace on the Korean Peninsula, its military most threatening to the 25 million people of Seoul and the sprawling area around the South Korean capital.

But with President Trump warning of unleashing “fire and fury” against North Korea and the North demonstrating its missiles can fly far beyond the peninsula, people across Asia are reconsidering. Increasingly, countries in the region, especially those hosting American military bases, are asking: Are they potential targets of North Korean retaliation?

On Wednesday, North Korea’s leader, Kim Jong-un, singled out the American territory of Guam as a potential target. North Korean missiles have also recently landed not far from the coast of Japan, a crucial United States military ally. South Korea remains the most likely target of any North Korean counterattack should the United States take military action to try to stop the North’s nuclear and missile programs.

Guam, a Key American Outpost

North Korea warned on Wednesday that it was considering a strike that would create “an enveloping fire” around Guam, a United States territory that is home to vital American military operations. Guam’s governor, Eddie Baza Calvo, played the down threat of a North Korean attack in a video address on Wednesday.

“I want to reassure the people of Guam that currently there is no threat to our island or the Marianas,” he said, referring to the nearby Northern Mariana Islands chain, a United States commonwealth. Mr. Calvo said officials and military commanders were “prepared for any eventuality.”

Guam is a potential target because it is a strategic American military outpost and home to nuclear-equipped bombers that can strike North Korea. Just this week two United States B-1 bombers flew from Guam over the Korean Peninsula. And North Korean missile tests suggest it is within range of the country’s arsenal.

While Guam is used to threats from North Korea, several residents said the current situation felt more dangerous — partly because of recent advances in the North’s weapons program, but also because of Mr. Trump’s rhetoric.

An American Army sergeant, who spoke on the condition of anonymity because he was not supposed to make political statements in public, complained that Mr. Trump had needlessly elevated the risk of a military confrontation with North Korea with his remarks. Continue reading.