Huawei’s research and development lab in the city of Dongguan, China is on fire, with large clouds of gray smoke billowing from the building, according to multiple videos posted to social media and the state news outlet Global Times. It’s not clear what caused the blaze, but firefighters are on the scene, according to China’s Sixth Tone news outlet, and there have been no reports of casualties.

People presumed to be Huawei employees, some dressed in white lab coats, can be seen fleeing the area. Some social media videos refer to an “explosion” but state media has only reported on a fire and there’s no immediate evidence to suggest any kind of “explosion” occurred.

Dongguan is located in Guangdong province, the site of Huawei’s $1.5 billion Songshan Lake campus. Huawei reportedly has roughly 25,000 employees there, a corporate park which gained widespread attention in U.S. media last year for its European-themed buildings.

Early reports indicate that the R&D lab may contain “sound absorbing materials,” like cotton, that are highly flammable, according to the Global Times. The building was reportedly under construction, suggesting that the number of people inside may have been minimal.

Several Chinese-based media outlets tweeted videos about the incident using videos posted to Weibo, a popular social media service it China, but some deleted their tweets without explanation.

The Global Times first tweeted video around 5:30 p.m. local time, 5:30 a.m. ET, but deleted the video less than 10 minutes later. Sixth Tone did the same thing, crediting their video to Fengmian News, but deleted it from Twitter rather quickly. Both sites appear to have reposted video and text roughly 30 minutes later similar to the content that was deleted. It’s not clear why the tweets were deleted and reposted.

A compilation video published to YouTube by China’s The Paper shows the fire from several angles. [Update, 7:20 a.m.: The Paper’s YouTube video was deleted for an unknown reason, but other videos have been reposted showing the blaze.]

President Donald Trump signed an executive order in 2019 banning Huawei from using U.S. tech, excluding it from much of the American market, especially when it comes to the development of 5G networks. But the company is still going strong in the rest of the world, with healthy growth from its smartphone market.