China Tuesday vehemently denied U.S. allegations that it carried out a massive Microsoft cyberattack Tuesday, countering that the U.S. was the "world champion" of cyberattacks and lashing out at American allies for signing a rare joint statement of condemnation.

The Chinese embassy in New Zealand responded quickly to the "totally baseless and irresponsible" charges.

It was backed up by the Australian embassy, as China took a coordinated stance of its own, accusing Canberra of "parroting the rhetoric of the U.S."

"It is known that the U.S. has engaged in unscrupulous, massive and indiscriminate eavesdropping on many countries including its allies," the embassy said in a statement.

"It is the world champion of malicious cyberattacks."

The U.S. Monday accused China of carrying out the March cyberattack on Microsoft and charged four Chinese nationals connected to the "malicious" hack.

The attack on Microsoft Exchange, a top email server for corporations worldwide, was part of a "pattern of irresponsible, disruptive and destabilizing behavior in cyberspace, which poses a major threat to our economic and national security," according to US Secretary of State Antony Blinken.

The U.S. Department of Justice announced at the same time that four Chinese nationals had been charged for hacking the computers of dozens of companies, universities, and government agencies in the U.S. and abroad between 2011 and 2018.

Blinken said that the U.S. "will impose consequences on (Chin) malicious cyber actors for their irresponsible behavior in cyberspace," referring to the indictment.

President Joe Biden told reporters that the U.S. was still conducting an investigation before taking any action, drawing parallels with the obscure but prevalent cybercrime attributed to Russia by Western officials.

"The Chinese government, not unlike the Russian government, is not doing this themselves, but are protecting those who are doing it, and maybe even accommodating them being able to do it," Biden told reporters.

The U.S. coordinated its statement Monday with allies - the European Union, Britain, Australia, Canada, New Zealand, Japan and NATO - in a move hailed as unprecedented by the Biden administration.

The Microsoft hack, which took advantage of vulnerabilities in the Microsoft Exchange service, affected at least 30,000 U.S. organizations, including local governments, as well as businesses worldwide.