WASHINGTON — The Justice Department on Wednesday unsealed charges against three North Korean intelligence officials accused of hacking scores of companies and financial institutions to thwart U.S. sanctions, illegally fund the North Korean regime and control American corporations deemed enemies of the state, including Sony Pictures Entertainment.

The charges are the government’s latest effort to show that North Korea has engaged in a brazen, yearslong effort to undermine and attack institutions around the world and steal millions of dollars even as the United States and its allies intensify efforts to rein in the country and its nuclear ambitions.

One of the officials, Park Jin-hyok, a member of North Korea’s military intelligence agency, was accused by the Justice Department in 2018 of participating in the Sony hacking that crippled the company, as well as the WannaCry cyberattack on Britain’s National Health Service, and an attack on the Bangladeshi central bank and financial institutions around the world.

Building on that investigation, the Justice Department indicted Mr. Park and two more North Korean spies, Jon Chang-hyok and Kim Il, on charges related to those attacks, as well as new accusations that they tried to steal more than $1.2 billion.

“Simply put, the regime has become a criminal syndicate with a flag, which harnesses its state resources to steal hundreds of millions of dollars,” John C. Demers, the head of the Justice Department’s National Security Division, said in a statement.

Prosecutors declined to say how much money the hackers actually obtained.

Separately, federal prosecutors charged Ghaleb Alaumary, 37, a dual citizen of the United States and Canada, with organizing a network of people in those countries to launder millions of dollars that the North Korean government obtained from the hackers. Mr. Alaumary pleaded guilty to the charge.

Wednesday’s broad indictment supports the findings of a report released this month by Recorded Future, a cybersecurity research group, that concluded that North Korea has greatly expanded its ability to use the internet to financially prop up its government even though the United States and its allies have choked…