Uber is learning a tough lesson about what happens when you go head-to-head with China’s tech giants on their own turf.

Tencent, the tech company that oversees the China’s most popular chat app WeChat, has has blocked all Uber accounts on its social platform, affecting the service across more than a dozen cities. 

Tencent-backed Didi Dache is the country’s biggest ride-hailing service and Uber’s largest competitor in the Chinese market. 

According to Tencent CEO Ma Huateng [Pony Ma], the recent ban was due to marketing violations by a series of companies, though some were punished more harshly given the severity of the violations, he says.

China Business Network (CBN) CEO Zhou Jiangong confirmed to Technode that Mr. Ma made the comments on a social media post within their personal network. 

Mr. Ma explained that public accounts of a certain size have the ability to “incite”, and that Chinese national regulations require businesses of a certain size to hold an Internet Content Provider license (ICP).

“The platform treats everyone equally,” said Mr. Ma, “Didi also violated the rules,” he noted, saying that in the past Didi had also been subject to restrictions.

As of Monday Uber is the only ride-hailing service that has been formally banned from the WeChat platform.

It’s the latest blow in an escalating war for market supremacy between California-based Uber and their Chinese equivalent Didi, backed by the country’s two biggest tech companies Alibaba and Tencent. 

China’s largest internal ride-sharing war came to an end with the merger of Alibaba’s Kuaidi Dache with Tencent’s Didi Dache in February 2015. The landmark merger was the beginning of a global ride-hailing empire that includes Singapore’s GrabTaxi, India’s Ola and Canada’s Lyft. The coalition now poses a formidable front against Uber’s expansion, especially in Asia where the U.S. company has been seeking to expand. 

Uber’s accounts were previously blocked on WeChat from mid-March. At the time local media reported that the the issues were due to policy violations, and later technical glitches.

According to Mr. Ma the latest bans are part of a platform-wide cleanup effort to remove accounts that are marketing their products by malicious means.

The loss of their public WeChat accounts is a big blow for the China-side operations of Uber. WeChat is a significant consumer outreach platform for businesses on the mainland, with over 10 million public accounts.