Iranian hackers linked to the Islamic Revolutionary Guard Corps broke into computer systems of more than 300 universities worldwide and stole valuable research, the U.S. Department of Justice said in an indictment unsealed March 23.

According to the indictment, the nine hackers worked for an Iranian company called the Mabna Institute. Since 2013, the company has conducted a campaign to steal terabytes of data — roughly 15 billion pages of academic research and intellectual property. The hacks also targeted businesses around the world, U.S. state and federal government systems and the United Nations.

The Islamic Revolutionary Guard Corps, the notorious Iranian paramilitary and intelligence organization, appears to be behind the hacks, according to the charging document.

President Trump recently denounced the corps as “a hostile army that brutalizes and steals from the Iranian people to fund terrorism abroad.”

Universities in the U.S., Australia, Canada, China, Germany, Japan, Israel, South Korea and the United Kingdom, as well as many others, suffered from intellectual property theft. The hackers targeted research on science and technology, engineering, medicine and other subjects at institutions in more than 20 countries.

While it is impossible to put a price on the value of the hacked material, the U.S. universities alone spent $3.4 billion to collect the research, the Justice Department said.

U.S. Attorney Geoffrey S. Berman said hackers could no longer hide behind the anonymity of computer code. “These defendants are now fugitives from American justice, no longer free to travel outside Iran without risk of arrest,” he said.

Rod Rosenstein, the deputy attorney general at the U.S. Department of Justice, said the type of criminal activity laid out in the indictment does not only cause economic harm, but also threatens U.S. national security.

Rosenstein cautioned that an indictment is not a finding of guilt. “In the American judicial system, defendants are presumed innocent unless and until they are proven guilty in a court of law,” he said.

The U.S. Department of the Treasury also targeted the Mabna Institute and 10 Iranian individuals for sanctions.