"The first shot will be cyber," it quoted a former U.S. intelligence official as predicting. Quoting six former and incumbent U.S. intelligence officials, the magazine wrote, "The U.S. government for the past six months has covertly begun laying the groundwork for possible cyberattacks on North Korea in countries including South Korea and Japan."

Despite talk of a "bloody nose" strike against North Korea in Washington, the initial round of warfare could be waged in cyberspace, according to Foreign Policy magazine.

"This process involves installing fiber cables as bridges into the region and setting up remote bases and listening posts, where hackers may attempt to gain access to a North Korean Internet that's largely walled off from external connections," it added.

"America's spies are pivoting the magnifying glass, funneling much of the weight of billions of dollars in technical infrastructure and trained professionals toward Pyongyang," it said. "Military and intelligence contractors have posted a number of job announcements in recent months seeking analysts with Korean-language skills, including positions to identify and recruit human intelligence sources."

Top-notch analysts have been assigned to a Korean affairs division at the Defense Intelligence Agency. "In November 2017, rumors flew around the halls at CIA headquarters in Langley, Virginia that the agency would also be surging analysts of all disciplines to work at the brand-new Korea Mission Center, established in May of that year, a symbol of serious potential for military action."

Counterterrorism and drug specialists have been given new jobs related to the Korean Peninsula or will likely be given such jobs soon, according to the magazine. There is "a nearly unprecedented scramble inside the agencies responsible for spying and cyber warfare" against the North.

Washington could fire "a warning shot" at Pyongyang over the cryptocurrency market, given CIA Director Mike Pompeo's recent remarks that a "maximum pressure" campaign against Pyongyang was designed by the CIA and that Washington is preparing a series of options in case diplomacy fails, the magazine speculated.

The North is reportedly siphoning off cryptocurrencies by hacking bitcoin exchanges as it is now difficult to earn hard currency due to U.S.-led sanctions.