Instant messaging system Telegram has been blocked in China following a massive cyber attack against the company’s Asia-Pacific operations.

According to blockedinchina.net, access to Telegram’s web-version has been blocked from servers located in Beijing, Shenzhen, Inner Mongolia, Heilongjiang and Yunnan.

Telegram’s status on Monday morning. Photo: blockedinchina.net.

In a People’s Daily article on Sunday, the Berlin-based messenger was singled out for aiding Chinese human rights lawyers, who have become the target of an “unprecedented” nationwide crackdown.

According to the state-run newspaper, “rights defence” lawyers used the application to communicate “attacks on the [Communist] Party and government.” Zhai Yanmin, a fixer for law firm Beijing Fengrui who “confessed” on national TV, said that “various support activities were planned and organised” by legal professionals on Telegram.

Referring to Telegram’s “Secret Chat” mode in which messages can be set to automatically self-destruct, Zhai said that communications were deleted at pre-set time intervals because the firm “didn’t want the government to know” what they said.

Telegram banned in China. Photo: Wikicommons/HKFP.

On Friday morning, Telegram’s Asia Pacific server cluster fell under a distributed denial of service (DDoS) attack, disrupting service for users in South East Asia, Oceania and Australia.

In an official statement, Telegram said that they “know the attack is being coordinated from East Asia,” noting a three-fold increase in signups from South Korea over the preceding two weeks.

Speculation online has attributed the attack either to Korean rivals Kakao Talk and Line, said to be unhappy with Telegram’s free sticker platform, or the Chinese state. Telegram itself, however, has not offered theories on the source of the attack.

Telegram is run by a German nonprofit headed by Russian philanthropist Pavel Durov. It allows users to exchange messages encrypted end-to-end, offering greater privacy than alternative platforms.

Last year, millions of South Korean users migrated to the app after Seoul imposed tough new restrictions on online communications, promising to store and monitor messages and punish those that insulted the president or spread “rumours.”

Kakao Talk and Line, which earn around 20 per cent of their revenue by charging users for digital “stickers,” were both banned in China in July 2014, coinciding with Hong Kong’s annual pro-democracy march.