The concern is that even a limited strike, or a so-called "preventive attack" being pushed by some hawks in the Trump administration, could spark a major response from the North Koreans, according to experts. And, there's no guarantee a military strike by the U.S. won't result in a wider conflict or war on the Korean Peninsula.
"Seoul has very strong concerns about the potential for a U.S. 'preventive attack' on North Korea," said Bruce Klingner, former chief of the CIA Korea division and now senior research fellow for Northeast Asia at the Washington-based conservative think Heritage Foundation.
Adding to the anxiety is "nuclear button" rhetoric this month from North Korean leader Kim Jong Un and President Donald Trump as well as news reports that the White House is considering a possible pre-emptive "bloody nose" strike on North Korean missile facilities.
"Whatever we want to call it, war footing or not, a strike on North Korea has always been one of the options that various U.S. administrations have had in their toolbox," said Benjamin Silberstein, associate scholar at the Philadelphia-based Foreign Policy Research Institute.
Possible catalysts for the limited strike against North Korea could include the regime launching another intercontinental ballistic missile test or an atmospheric hydrogen bomb test, which it threatened to do last year.
Experts say the springtime historically has been an active period of missile testing by Pyongyang, when the regime complains about massive U.S.-South Korean joint military exercises.
The upcoming war games known as Foal Eagle and Key Resolve are set to get underway after the Olympics and involve American and South Korean ships, tanks and aircraft as well as live-fire exercises and more than 230,000 combined troops. The North Koreans view the war drills as provocative because they contain simulated elements sometimes described as "decapitation strikes" by special forces that target the regime's leadership.
Some proponents of the Trump administration's limited-strike option contend that the North Koreans might actually hold back from any military response out of fear that the risks of doing so are too great because it could produce a massive response from Washington and perhaps be fatal to the Kim regime. Yet others disagree, saying the North Korea leader would look bad if he didn't respond since the regime has blamed the U.S. for crippling international sanctions and its other problems. They also contend that a faction of the military could act on its own if Kim failed to order a military response.
"Kim would have no choice but to respond back or he'd face the possibility of a coup," said Harry Kazianis, director of defense studies at the Center for the National Interest, a U.S. think tank. "And maybe even respond more ferociously than we attack him."
Any retaliation could potentially pose a threat to the greater Seoul area, where about half of the South Korean population lives. North Koreans are known to have thousands of hardened artillery sites, including some dug into mountains, along the Korean DMZ and within range of Seoul.
Klingner, the former CIA official, just returned from a trip to South Korea where he heard firsthand the concerns of senior officials. He said the unanimous view is that even a limited strike would certainly trigger a response from the North Koreans.
"Some are suggesting that the U.S. is thinking of hitting two or three targets, and that North Korea would likely respond proportionately," Klingner said. "Not the all-out artillery barrage on Seoul."
Still, he said there are scenarios where a limited strike by Washington could result in a larger response by the North Korean military.
Another wildcard is what China would do if the U.S. were to conduct a strike against North Korea. An editorial last year in China's semi-official Global Times newspaper suggested Beijing might help North Korea if Washington launched a pre-emptive attack.
China was noticeably absent last week when diplomats from 20 countries met in Vancouver, British Columbia, to discuss the North Korean nuclear threat and international sanctions.
Secretary of State Rex Tillerson was asked at the meeting whether there might soon be military conflict with Pyongyang and responded: "I think we all need to be very sober and clear-eyed about the current situation. We have to recognize that the threat is growing. And if North Korea does not choose the path of engagement, of discussion, negotiations, then they themselves will trigger an option."
Some are critical of the Trump administration for giving mixed messages on North Korea and for what some call "loose talk" on military options. For example, Trump last year appeared to undercut diplomatic efforts by Tillerson by tweeting, "Save your energy Rex, we'll do what has to be done!"
"Mixed messages from the United States toward North Korea has plagued the Trump administration efforts to reduce the threat posed by the North's nuclear program from Day One," said Kelsey Davenport, director for nonproliferation policy at the Arms Control Association, a nonpartisan disarmament group based in Washington.
According to Davenport, the "uptick in loose talk" about a possible "preventive strike" risks hurting the momentum created by the inter-Korean talks over the Olympics and to advance diplomatic efforts and the denuclearization goal. Also, she said, "loose talk of 'preventative war' also is dangerous because it increases the likelihood of miscalculation or inadvertent escalation in the region."
Regardless, many don't see the North Korean leader giving up his nuclear weapons anytime soon. They say the regime is well aware of what happened with Libya's Moammar Gadhafi when he gave up his nuclear weapon ambitions after facing Western pressure.
"They've been very clear that they have no intention ... to give up 1 inch on their nuclear weapons development," said Silberstein. "That's still where we're at, regardless of how many North Korean athletes come to Pyeongchang."