Satellite images appear to show a train likely belonging to North Korean leader Kim Jong Un has been parked at his compound on the country's east coast since last week.
The images come amid speculation about Kim's health, caused in part by a long period out of the public eye.
The satellite photos released by 38 North, a website specialising in North Korea studies, don't say anything about Kim's potential health problems, and they echo South Korean government intelligence that Kim is staying outside of the capital, Pyongyang.
Seoul has also repeatedly indicated that there have been no unusual signs that could indicate health problems for Kim.
That hasn't stopped growing unconfirmed rumors and media reports about Kim's health that have emerged since he missed an April 15 commemoration of the 108th birthday of his grandfather and North Korea founder, Kim Il Sung.
Kim Jong Un is the third generation of his family to rule North Korea, and he hadn't missed the April 15 event, one of the year's most important for the North, since assuming power after his father Kim Jong Il's death in late 2011.
Kim's health is of crucial importance because of worries that the serious illness or death of a leader venerated with near godlike passion by millions of North Koreans could cause instability in the impoverished, nuclear-armed country.
Many experts in South Korea downplayed speculation that Kim is seriously ill.
They also said North Korea won't likely face a serious immediate turmoil even if Kim is incapacitated or dies because someone else like his influential sister Kim Yoo Jong will quickly step in, though the prospect for the North's long-term political future would be unclear.
Kim Jong Un's train has been parked at the Leadership Railway Station servicing his Wonsan compound since at least April 21, the website 38 North said on Saturday, citing an analysis of recent satellite photos of the area.
The website said that the approximately 250-metre train wasn't present on April 15 but was present on both April 21 and 23.
"The train's presence does not prove the whereabouts of the North Korean leader or indicate anything about his health, but it does lend weight to reports that Kim is staying at an elite area on the country's eastern coast," it said.
North Korea exerts extremely tight control on information about its leadership, making it virtually impossible for outsiders to find out what's going on at those senior levels.
It's not the first time that Kim has vanished from the public eye, and past absences in state media dispatches have also triggered speculation about his health.
In 2014, state media didn't report any public activities for Kim for about six weeks, before he reappeared with a cane. South Korea's spy agency said later that he had a cyst removed from his ankle.
Australian Associated Press