Tencent Holdings said it will shut down a service that allowed Chinese gamers to access overseas platforms to play unapproved foreign games, in a sign of tightening compliance as Chinese regulators more closely scrutinize the industry.

The country’s largest social and gaming firm said late on Wednesday it will on May 31 update its games speed booster mobile and desktop apps to new versions that would only support games operating in China.

The new versions will no longer allow users to new versions that would only support games operating in China. The new versions will no longer allow users to access foreign games.

Tencent first launched the apps in 2018. Such apps, which other companies like NetEase Inc also offer, act as network acceleration tools that help users boost their internet speeds.

Unlike most countries, gamers in China are only allowed to play titles approved by the government and are not allowed to play with foreigners on foreign servers. While such foreign games are not explicitly blocked by online curbs, local internet speeds are generally too slow for gamers to access them.

As such, many gamers in China used such apps in practice to access unapproved foreign games such as Grand Theft Auto or Nintendo Co’s smash-hit Animal Crossing. The apps also over the years became grey-area channels for foreign game developers to reach users in the world’s largest gaming market.

Tencent declined to provide further comment on why it had decided to make changes to the app.