The Biden administration revealed Monday that China-backed hackers infiltrated the U.S. Treasury Department earlier this month in what officials are calling a "major cybersecurity incident."

The US Treasury Department notified lawmakers on Monday that a China state-sponsored actor infiltrated Treasury workstations in what officials are describing as a “major incident.”

Cyber warfare has been increasing in recent years: In March, the US and Britain accused another Beijing-backed group of hacking millions of people over more than a decade, including journalists and academics, while other hackers apparently targeted US President-elect Donald Trump’s phone and that of his running mate in October.