LONDON: Britain on Monday accused Chinese hackers of trying to break into the email accounts of British lawmakers who were critical of China and said a separate Chinese entity was behind a hack of its electoral watchdog that compromised millions of people’s data.

In response to the attempted hack in 2021 of emails belonging to British politicians “prominent in calling out the malign activity of China”, Britain imposed sanctions on two people and one company linked to state-backed Chinese hacking group APT31, the Foreign Office said in a statement.

It also said an unidentified Chinese state-affiliated hacking group was behind a separate 2021-2022 cyber-attack on Britain’s Electoral Commission. That hack was disclosed last year but Britain had not previously said who was responsible.

Foreign Secretary David Cameron described the hacks as “completely unacceptable”, according to the statement.

The Chinese embassy in London did not respond to requests for comment.

The British government is attempting to strike a delicate balance between trying to neutralise security threats posed by China while maintaining or even enhancing engagement in some areas such as trade, investment and climate change.

But there has been growing anxiety about China’s alleged espionage activity in Britain, particularly ahead of a general election expected later this year.

Tensions between Beijing and Western powers over issues related to cyberespionage have been rising as Western intelligence agencies increasingly sound the alarm on Chinese state-backed hacking activity.

Last month, security officials told Reuters that the US government had launched an operation to fight a pervasive Chinese hacking operation that compromised thousands of internet-connected devices. Days later, Dutch intelligence agencies said Chinese cyberspies had gained access to a military network in The Netherlands in what they said was a trend of Chinese political espionage.

APT31, the Chinese hacking group behind the targeting of British lawmaker emails, has a history of spying on politicians and their staff. In 2020, security researchers at Google and Microsoft warned that the group had targeted the personal emails of campaign staff working for US President Joe Biden. According to US cybersecurity firm Secureworks, APT31 has also targeted legal, consulting, and software development firms.

Britain has spent the last year trying to improve ties with China after the relationship sunk to its lowest point in decades under former Prime Minister Boris Johnson, when London restricted some Chinese investment over national security worries and expressed concern over a crackdown on freedoms in Hong Kong.