While the White House said it was conducting an investigation into the hacking of federal government accounts, Microsoft blamed a hacker group from China.
White House National Security Adviser Jake Sullivan said the United States very quickly discovered a hack targeting federal government accounts, noting that Microsoft announced the breach.
He explained that the US administration was quickly able to prevent further breakthroughs.
Speaking to ABC's "Good Morning America," Sullivan said, "We discovered it very quickly and were able to prevent further intrusions," adding, "The investigation is still ongoing."
Microsoft software and technology company investigates spying of its customers (Reuters)
Espionage operations
Microsoft software and technology said a China-based hacking group carried out espionage operations during which it hacked into a series of email accounts linked to government agencies in Western Europe.
The news agency quoted "Bloomberg" on Wednesday from Microsoft as saying that the hacking group bears the name "Storm-0558" (Storm-0558), and was able to continue without being discovered for a month, after it obtained in mid-May / May data on an email belonging to about 25 bodies and organizations.
The US software company only discovered the breach after an investigation in mid-June, after it was alerted by customer reports about abnormal email activity.
Charlie Bell, executive vice president at Microsoft, wrote, "We appreciate that this adversary focuses on espionage, such as accessing email systems in order to gather intelligence."
Microsoft said it had notified affected customers and made efforts to mitigate the effects of the hacking.