The ICC, based in the Dutch city of The Hague, first disclosed a 'cybersecurity incident', saying it was trying to ensure the tribunal's 'core work' continued.

The ICC is the permanent war crimes tribunal in the Dutch city of The Hague, established in 2002 to try war crimes and crimes against humanity.

David Bradbury, chief security officer of the identity management company Okta, said five of the company's clients had fallen victim to hacking groups known as ALPHV and Scattered Spider since August.

Vladislav Klyushin was sentenced by US District Judge Patti Saris in Boston after a jury found him guilty in February.

The hacking group behind this activity, known in the industry as Midnight Blizzard or APT29, is based in Russia and the UK and US governments have linked it to the country's foreign intelligence service.

Cybersecurity researchers have demonstrated a variety of potentially malicious use cases and some now say they are beginning to see suspected AI-generated content in the wild.

The espionage has also targeted the US island territory of Guam, home to strategically important American military bases, Microsoft said in a report, adding that 'mitigating this attack could be challenging.'

China's foreign ministry says it was 'not aware' of any such hacking, while China's embassy in Britain calls the accusations 'baseless', adding that Beijing opposes and combats 'cyberattacks and theft in all their forms.'

The hackers started leaking data after Medibank – the country's largest health insurer – refused to pay a US$9.7 million (about RM45 million) ransom.

The hacking was discovered in the summer when Truss was foreign minister and campaigning to become party leader and the next prime minister, The Mail reports.

The website of Taiwan's presidential office was targeted by a distributed denial of service (DDoS) attack and was at one point malfunctioning.

An unsealed redacted affidavit described the unusual operation as a pre-emptive move to stop Russian hackers from mobilising the compromised devices into a 'botnet' .