WASHINGTON (AP) " U.S. officials say two Chinese citizens acting on behalf of their country's main intelligence agency carried out an extensive hacking campaign to steal data from government agencies and companies in the United States and nearly a dozen other nations. It was the latest in a series of Justice Department indictments targeting cyberespionage from Beijing.

The two are accused of breaching computer networks in a broad swath of industries, including aviation and space and pharmaceutical technology.

All told, prosecutors say, the alleged hackers " identified as Zhu Hua and Zhang Shillong " stole "hundreds of gigabytes" of data, breaching computers of more than 45 entities in 12 states. They are not in custody and the United States does not have an extradition treaty with China.

U.S. law enforcement officials described the case as part of a trend of state-sponsored hackers breaking into American networks and stealing trade secrets and confidential and valuable information.

"China's state-sponsored actors are the most active perpetrators of economic espionage," FBI Director Chris Wray said Thursday in announcing the case. "While we welcome fair competition, we cannot and will not tolerate illegal hacking, stealing or cheating."

Last week, officials from the Justice Department, the FBI and the Department of Homeland Security testified to the Senate Judiciary Committee that China is working to steal trade secrets and intellectual property from U.S. companies in order to harm America's economy and further its own development.

Chinese espionage efforts have become "the most severe counterintelligence threat facing our country today," Bill Priestap, the assistant director of the FBI's counterintelligence division, told the committee.

In the last several months, the Justice Department has filed charges against several Chinese intelligence officials and hackers. A case filed in October marked the first time that a Chinese Ministry of State Security officer was extradited to the United States to stand trial.