Cyber threats from China and its theft of intellectual property from American companies pose large economic and national security challenges for the United States, national security officials said Wednesday.

Officials from the Department of Justice, the FBI and the Department of Homeland Security told 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.

“We cannot tolerate a nation that steals the fruit of our brainpower,” Assistant Attorney General John Demers said.

Bill Priestap, the assistant direct of the FBI’s counterintelligence division, said federal officials are doing everything they can to convey the current threat to business leaders and government officials.

China’s espionage activity has been “steadily increasing” in the last few years, Demers said.

“The bottom line is they will do anything they can to achieve their aims,” Priestap said of the Chinese.

Cyberespionage cases can be drawn out, involve sensitive intelligence and ultimately may not lead to prosecutions, he said. The department is working to train prosecutors across the U.S. in how to bring similar cases.

In the last few months, the Justice Department has filed several charges against Chinese hackers and intelligence officials.

In October, a suspected Chinese spy was charged with attempting to steal trade secrets from several American aviation and aerospace companies. Yanjun Xu, an operative of the Chinese Ministry of State Security, is accused of recruiting employees of major aerospace companies, including GE Aviation, and persuading them to travel to China under the guise of giving a presentation at a university.

That case was the first time that a Chinese Ministry of State Security intelligence officer has been extradited to the United States for trial.

Tensions between the U.S. and China have been high recently because of trade disputes, and President Donald Trump frequently criticizes China.

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