He's the latest in a series of top aides to young North Korean leader Kim Jong Un who are reported to have died in recent years.
The state-run Korean Central News Agency (KCNA) provided no further details Wednesday on the death of Kim Yang Gon, 73, who was a veteran of negotiations with South Korea since the era of former leader Kim Jong Il.
Kim Yang Gon played a prominent role in talks to defuse tensions
between the two sides after an exchange of artillery fire in August. He was the head of the United Front Department, the main agency responsible for dealings with South Korea.
"He was surely trusted by the Kim family regime," said Greg Scarlatoiu, executive director of the Committee for Human Rights in North Korea. "The one who appointed him head of the United Front Department was Kim Jong Il, the father of the current leader. And what we knew was that he was really close to young Kim Jong Un."
The young leader paid his respects in person at Kim Yang Gon's funeral bier, state media reported, publishing photos of the visit. "He looked bitterly sorrowful, when seeing the face of the beloved comrade-in-arms," KCNA said Thursday.
Analyst: 'I'm puzzled'
Numerous senior officials under Kim Jong Un are believed to have been purged since he took power four years ago. The most dramatic example was the young leader's uncle Jang Song Thaek, who was executed in 2013
and described by state media as "despicable human scum."
KCNA used very different language for Kim Yang Gon after his death, reporting that Kim Jong Un called him "a faithful revolutionary soldier." The ruling party accorded him a state funeral organized by top regime officials, it said.
But some North Korea watchers raised questions about the circumstances of the senior official's death.
"His predecessor in the same position died in a car accident," said Han Park, a professor of international relations at the University of Georgia, referencing the 2003 death of Kim Yong Soon. "I'm puzzled. I'm extremely puzzled."
Park, who helped secure the release of two American journalists detained in North Korea
in 2009, said he doubted that there had been any disagreement between Kim Yang Gon and Kim Jong Un.
But he noted that "traffic accidents are very uncommon" in North Korea.
Another analyst told CNN that a "suspicious" number of high-ranking North Korean officials have met their end in car accidents.
"Security is extremely tight when a high(-ranking) official is traveling through essentially empty streets. Yes they are known that they love to speed. So occasionally such incidents might happen," Andrei Lankov, a professor at Seoul's Kookmin University, said.
"However, there is another reason to be highly suspicious. If you look at the North Korean history, we can see that a surprising large number of their high level North Korean officials have died in car crashes."
North Korea's veil of secrecy
The North Korean regime is famous for its secrecy and isolation, making it unlikely it will give a full account of what happened to Kim Yang Gon. The KCNA report didn't even mention where the car accident took place.
Scarlatoiu of the Committee for Human Rights in North Korea, which seeks to expose abuses by the regime, said that former leader Kim Jong Il, who died in 2011, was believed to have staged the deaths of top aides in car accidents.
Kim Jong Un, meanwhile, is estimated to have had scores of senior officials killed since he took power, South Korea's National Intelligence Service (NIS) reported in April
Clear confirmation of such information from inside the reclusive North Korean state is difficult, however.
Reports of the deaths often come from the NIS, defectors or other sources rather than North Korean state media.
In May, reports citing the NIS
suggested that Hyon Yong Chol, the North Korean defense minister, had been executed. North Korean state media later confirmed he had been replaced, but whether he was killed remains unclear.
Regardless of the circumstances of Kim Yang Gon's death, his absence could disrupt the dialogue between Pyongyang and Seoul, said Cheong Seong-chang, a senior researcher with the Sejong Institute, a South Korean think tank.
The South Korean government said it had sent a letter of condolence Wednesday to North Korea regarding Kim Yang Gon's death.