Choi Kang, vice president of the Asian Institute for Policy Studies, says the timing of the "grey area" provocation shows Kim is still in charge of the North Korean military.
South Korea responded by firing two shots toward North Korea; no injuries were reported.
"We can confirm at least the initial reports are that you've described are just about right". "A handful of shots that came across from the North. We think those are accidental", Mr. "So far as we can tell, there was no loss of life on either side".
The government official declined to provide reasons, but said speculative reports that Kim had had an operation, citing some differences in his leg movements, were untrue.
"U.S. -North Korea talks going nowhere; Kim Jong Un pushing the envelope, say through short-range missile tests; Trump hoping that nothing much happens at least through the November elections".
The two neighbors remain technically at war, after fighting in the Korean War was halted with an armistice in 1953.
The incident came just one day after North Korean leader Kim Jong Un reappeared in public after a almost three-week absence that fueled speculation he was gravely ill or perhaps had died.
The North Korean leader was reportedly seen for the first time publicly in three weeks at the completion ceremony for a fertiliser plant in Pyongyang on May 1.
Donald Trump said that he was "glad" that his North Korean counterpart had re-emerged and appeared to be healthy.
Kim Jong Un was not spotted in the public eye for three weeks, and missed out on two important holiday celebrations.
As for North Korean media, it issued a series of statements about Kim's regular back-and-forth communications with officials, foreign leaders, and construction workers in Samjiyon, a model city in the country's north.
It is the first reported exchange of gunfire between the two Koreas along the border since 2017, when the North fired bullets at one of its soldiers who was fleeing to the South.
"It looks like Chairman Kim is alive and well".
In 2014, Kim disappeared for about 40 days, eventually reemerging with a cane.
His absence triggered a series of unconfirmed reports over his condition, while the United States and South Korea insisted they had no information to believe any of the conjecture was true.
On Thursday, U.S. Secretary of State Mike Pompeo said Washington was monitoring the situation closely and that the U.S. focus remained on "making sure that that country doesn't have nuclear weapons."North Korea has shown no willingness to abandon weapons it sees as vital for defense of the nation and the Kim dynasty".