Internet startup Beijing Bytedance was ordered by China’s State Administration of Radio and Television to delete a joke sharing app because it contained “vulgar and improper content”.

The agency said the app, Neihan Duanzi, had caused “caused strong disgust amongst netizens”, media reports stated. The company’s news app Toutiao (along with Phoenix News, NetEase News and Tiantian Kuaibao) was temporarily suspended from some Chinese app stores and its music-themed video platform Douyin was ordered to stop its live-streaming functions.

In a public letter titled Apology and Introspection, Beijing Bytedance founder Zhang Yiming said: “The product took the wrong turn. The content that appears goes against core socialist values…we accept the penalty and I take full responsibility for it.”

The company will increase the number of content editors from 6,000 to 10,000.

Deleting the app is part of a government strategy to tighten its grip on online youth culture. Livestreams, blogs and mobile gaming are also being targeted.

Beijing Bytedance is one of the country’s fastest-growing tech startups and in 2017 was valued at around $20 billion.