Chinese officials denied carrying out a huge breach of critical Microsoft systems on Tuesday, calling US allies' claims "baseless" and "irresponsible." In China's first official response, embassies in Australia and New Zealand delivered statements of denial.

The charges were described by the Chinese embassy in Wellington as "completely baseless and irresponsible" and a "malicious smear." On its part, the Chinese embassy in Canberra accused Australia of "parroting" US language and described Washington as "the world champion of harmful cyber strikes."

Simultaneously, US Secretary of State Anthony Blinken said in a statement that the US government and its allies "formally confirmed that cyber actors affiliated with China's Ministry of State Security (MSS) exploited vulnerabilities in Microsoft Exchange Server in a massive cyber-espionage operation that indiscriminately compromised thousands of computers and networks, mostly belonging to private sector victims.”

In joint statements, NATO, the European Union, Australia, Britain, Canada, Japan, and New Zealand blamed China for the hacking of the Microsoft Exchange email server that compromised tens of thousands of computers around the world earlier this year.

On his part, President Joe Biden accused the Chinese authorities of “protecting” the perpetrators of these attacks, and even “providing them with the means to carry them out.”

A cyber-attack is an electronic attack carried out by computers via the Internet and digital communications networks with the goal of changing or disabling programs, destroying data, stealing information, or penetrating control and command systems with the goal of causing damage to other party's systems, programs, and devices and disrupting their ability to work.