North Korean leader Kim Jong Un hasn't been publicly seen in 2 weeks, fueling reports and rumors that he may be dead or in grave condition. Here's what we know.

• Speculation mounted on Saturday that North Korean leader Kim Jong Un may be dead or in grave condition after a surgery.
• The rumors started started after Kim did not appear at a celebration for one of the secretive state's most celebrated holidays on April 15 — the birthday of founder Kim Il Sung.
• Experts have previously noted he had certain health risks and could suffer cardiac issues due to his weight.
• Visit Business Insider's homepage for more stories.

Speculation mounted on Saturday over North Korean leader Kim Jong Un's health as he hasn't been seen in public since April 11 when he presided over a party meeting.

It's fueled reports from multiple outlets citing sources in China and Japan that Kim, who is believed to be 36, is in grave condition after a cardiovascular surgery or may even be dead. The South Korean government has denied the reports and said Kim is running the country.

President Trump said earlier this week the US had no reliable information regarding Kim's health. No country, including South Korea and China, has been able to confirm developments on his health status.

The speculation about Kim began after he did not appear at a celebration on April 15 commemorating the birth of Kim Il Sung, his grandfather and the founder of North Korea. The birthday is the country's most important holiday.

Reuters later reported on Friday that China dispatched a team of medical experts to travel to North Korea and advise on Kim's health, citing three sources. But the outlet was quick to note it wasn't able to determine what the development meant about the North Korean leader's health.

It's extremely difficult to verify reports about North Korea, long one of the world's most secretive states. State media outlets in North Korea have been silent so far about Kim's absence from public events.

North Korea watchers say that one of Kim's biggest risk factors were his poor health, particularly risks from cardiac issues due to his hefty weight, per The Washington Post's Anna Fifield.

"The young leader looks like a heart attack waiting to happen and has clearly had problems," Fifield wrote in her book, "The Great Successor."

North Korean leaders have previously disappeared only to reappear at public events weeks later

Back in 2014, the North Korean leader disappeared for nearly five weeks, fueling rumors he suffered from gout, a severe hangover or had been overthrown in a coup.

North Korean state TV later showed Kim walking with a cane and announced he wasn't "feeling well."

The same happened for the country's previous leader, Kim Jong Il. In 2008, he was publicly absent for several months. It was later confirmed he suffered a stroke, The New York Times reported.

When Kim Jong Il died in