China escalated attacks against the mining industry Thursday, adding mulitple mining pool IP addresses to its infamous “Great Firewall.”

Bitcoin and Ethereum mining pools BTC.com, Poolin, Binance Pool, ViaBTC and F2Pool suffered major DNS outages Thursday as Chinese regulators blacklisted addresses inside the country, according to numerous reports and tweets. ViaBTC’s domain was still inaccessible from the US as of publishing time.

Bitcoin’s hashrate – an estimate of the Bitcoin network’s mining activity – dropped slightly on the event, but not within a noticeable margin. Rather, multiple mining pools experienced lower or zero hashrate across different supported pool products.

According to The Block, China Telecom has issued new guidance for seeking and blocking IP addresses connecting to mining pools. The top 10 mining pools are now inaccessible in China.

The crackdown comes after months-long efforts by Chinese regulators to hamstring the cryptocurrency mining industry inside the country. Bitcoin mining was banned across multiple Chinese provinces last June followed by prohibitions against crypto-to-crypto transactions in September.

The Cambridge Center for Alternative Finance (CCAF) newest model released in October stated 0% of Bitcoin’s global hashrate was located in the region. However, expert opinions place the value at around 10-20% of the total Bitcoin network hashrate. The firewall extension implies the Chinese government is aware of stragglers in the region and are taking technical avenues to force a cessation of activities.

Mining pools were already divesting themselves from the region entirely by geo-blocking Chinese miners. BTC.com, Antpool, F2Pool and others banned China-based IP addresses in October.