Story highlights Posts on China's version of Twitter claim Kim Jong Un was assassinated

A senior U.S. official says intelligence shows no evidence the rumor is true

Kim Jong Un assumed leadership of the country following his father's death in December

The U.S. intelligence community has found no evidence to suggest North Korean leader Kim Jong Un is dead, a senior U.S. official said Friday following posts on China's version of Twitter that claimed Kim had been assassinated while in Beijing.

U.S. intelligence officials have been looking into such rumors for more than a week, according to the official, who has direct knowledge of the latest U.S. analysis.

"With that society you can never be 100% sure, but we just don't see any evidence of it," the official told CNN. "It's a closed society, but at this point we do not believe it's true."

The preliminary analysis of the rumor suggests it is part of a "calculated effort to disrupt the economy of South Korea at a fragile time by suggesting things are going haywire up north," the official said.

Meanwhile, the official added, "there is no evidence of movement of North Korean forces or activity that you would associate with the turmoil of a calculated assassination."

Kim, who is believed to be in his late 20s, assumed the title of "supreme leader" after his father Kim Jong Il's death in December at the age of 69. Kim Jong Il had ruled the reclusive nation since 1994.

The official pointed out that even during the recent peaceful transition of power, there were signs of troops being put on a higher state of alert.

Neither Chinese state media nor South Korea's Yonhap news agency addressed the rumor in their reporting.