The deputy director of the Federal Bureau of Investigation was blunt Thursday when describing what he said was the threat to American companies from China.

“ Nearly every one of our 56 FBI field offices throughout this nation has investigations into economic espionage that lead back to the country of China. We have had cases where actors have targeted corn seeds in the field of Iowa, software for wind turbines in Massachusetts, and in this case, complex semiconductor memory technology from a company based in Boise, Idaho. The Chinese government is not pulling any punches. ”

Attorney General Jeff Sessions announced a new initiative to combat Chinese espionage as he unveiled the charges against those who tried to steal secrets from Micron Technology MU, +2.23% .

An indictment alleges state-owned Chinese company Fujian Jinhua Integrated Circuit, Taiwan’s United Microelectronics UMC, +3.14% and three Taiwan individuals tried to steal secrets from Micron, which has up to a quarter of the market share in the dynamic random access memory microchip market.

The case revolves around Stephen Chen, who was president of a Micron subsidiary in Taiwan after an acquisition by the U.S. company. Chen resigned from Micron Memory Taiwan in 2015 and then started work for UMC, which had a joint DRAM technology venture with Fujian Jinhua.

According to the indictment, Chen recruited many of his former employees, including two who allegedly stole and brought to UMC several Micron trade secrets related to the design and manufacture of DRAM.

Attorneys for Fujian Jinhau, UMC, Chen and the two others couldn’t immediately be identified.

UMC shares fell after the indictment was announced. Micron shares jumped 6%.

The U.S. and China are in the midst of a trade war, with each brandishing tariffs against the other. The rate of tariffs on some $200 billion worth of Chinese goods imported into the U.S. is set to jump to 25% from 10% at the start of next year.

One key complaint made by U.S. officials is that Chinese companies steal technology from American firms.