As tensions climb to historic highs between the US and its allies and North Korea, rumors of massive movements of Chinese troops near North Korea's border keep surfacing.

A Pentagon official told Business Insider that the US had heard the reports but had "not seen anything to corroborate it."

But Chinese troops are always stationed in the northeast near North Korea, and Yun Sun, a senior associate with the East Asia Program at the Stimson Center, told Business Insider that "Chinese troop movements happen often along that border" when North Korean nuclear and missile provocations seem imminent.

"When North Korea acts up with some sort of provocation, the Chinese in the past have moved their troops to reinforce their deployments in the northeast for military preparedness," Yun said.

"On the other hand," Yun said, "I think it does signal that the Chinese are concerned about a potential escalation, or even potential conflict" between the US and North Korea, as North Korea plans a nuclear test and the USS Carl Vinson aircraft carrier pulls up to Korea's coast.

This footage purporting to show a massive movement of Chinese forces has surfaced online, further stoking the rumors:

On Saturday, North Korea will celebrate the 105th anniversary of the birth of Kim Il Sung, the founder of the Hermit Kingdom's Kim regime.

Experts have said Pyongyang has a nuclear device ready to test, and the US has signaled a loss of patience with North Korea pursuing nuclear weapons with the intent of one day threatening the US.