(Bloomberg) -- China arrested over 1,100 people in a sweeping crackdown on the use of cryptocurrencies for money laundering, adding to signs it’s further reining in crypto-linked activities.

Police busted more than 170 criminal groups that used cryptocurrencies to launder money in telecom scams to avoid being tracked down, the Ministry of Public Security said in a statement. The campaign spanned 23 provinces and cities, it added. Arrest figures were as of Wednesday afternoon.

The criminal groups needed to hire people to help with the laundering process because the bank accounts they used for such scams had been seized. Those hired would register their own bank accounts on virtual currency platforms, and use the money received from the criminal groups to trade virtual currencies before transferring those assets to the groups’ designated digital wallets. They were offered 1.5% to 5% commissions, which had lured many people into being accomplices in scams that caused “serious social harm,” according to the ministry.

China escalated its crypto crackdown this year after a frenzied surge in Bitcoin and other tokens at the beginning of 2021 heightened longstanding government concerns about the potential for fraud, money laundering and trading losses by individual investors. Regulators have so far stopped short of labeling individual trading illegal but the public security department will be involved in the crackdown, a person familiar with the matter had told Bloomberg last month.

Searches for crypto exchanges on China’s Internet are currently being censored. Keyword searches for popular crypto exchanges like Binance, OKEx and Huobi on Internet services such as Baidu, Sogou, Zhihu and Weibo yielded no results as of Thursday afternoon.

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