Chinese bitcoin exchange BTCChina said on Thursday it will stop all trading from Sept. 30. It did not elaborate on why.

BTCChina, which also runs an international exchange out of Hong Kong, also said on its official microblog that it would stop registration of new users from Thursday.

China has boomed as a cryptocurrency trading venue in recent years as its domestic exchanges had previously allowed users to conduct trades for free, attracting investors and speculators who boosted demand.

However, regulators have cracked down on the industry amid concerns that Chinese investors are speculatively piling into cryptocurrencies. Last week, they banned so-called "initial coin offerings," or the practice of creating and selling digital currencies or tokens to investors in order to finance start-up projects.