The Biden administration on Monday blamed China for a hack of Microsoft Exchange email server that compromised tens of thousands of computers around the world earlier this year.

The administration and allied nations also disclosed a broad range of other cyberthreats from Beijing, including ransomware attack from government-affiliated hackers that have targeted companies with demands for millions of dollars. China’s Ministry of State Security has been using criminal contract hackers, who have engaged in cyber extortion schemes and theft for their own profit, according to a senior administration official. That official briefed reporters about the investigation on the condition of anonymity.

Meanwhile, the Justice Department on Monday announced charges against four Chinese nationals who prosecutors said were working with the Ministry of State Security in a hacking campaign that targeted dozens of computer systems, including companies, universities and government entities.

The announcements highlighted the ongoing cyberthreat posed by Chinese government hackers even as the administration has been consumed with trying to curb ransomware attacks from Russia-based syndicates that have targeted critical infrastructure, including a massive fuel pipeline. Even though the finger-pointing was not accompanied by any sanctions of Beijing, a senior administration official who disclosed the actions to reporters said that the U.S. has confronted senior Chinese officials and that the White House regards the multination public shaming as sending an important message.

That hackers affiliated with the Ministry of State Security carried out a ransomware attack was surprising and concerning to the U.S. government, the senior administration official said. But the attack, in which an unidentified American company received a high-dollar ransom demand, also gave U.S. officials new insight into what the official said was “the kind of aggressive behavior that we’re seeing coming out of China.”

The European Union and Britain also pointed the finger at China. The EU said malicious cyber activities with “significant effects” that targeted government institutions, political organizations and key industries in the bloc’s 27 member states could be linked to Chinese hacking groups.