Federal officials made a high-seas interception of hundreds of thousands of pounds of two different precursor chemicals that are used to make methamphetamine, a shipment they say came from China and was destined for the Sinaloa Cartel in Mexico.

Jeanine Pirro, United States Attorney for the District of Columbia, announced what officials called the largest ever bust of precursor chemicals being shipped to a foreign terrorist organization during a news conference in Pasadena, Texas, on Wednesday.

“Tons of chemicals that are used to create synthetic drugs like methamphetamine and fentanyl are shipped from China to Mexico in China’s undeclared war against America,” Pirro said.

Pirro said that 1,300 barrels containing 363,000 pounds of benzyl alcohol and 334,000 pounds of N-Methylformamide were seized from two different vessels on the high seas. Both chemicals, Pirro said, are precursor chemicals that could have been used to produce 420,000 pounds of methamphetamine.

Precursor chemicals are tightly controlled substances that can be used to create deadly drugs or explosives.

Pirro said the seizures happened on the high seas aboard two different vessels that came from a port in Shanghai, China, and were bound for Mexico. (Win McNamee/Getty Images, File)

Pirro declined to comment on the exact location where the chemicals were seized aboard the ships, though she said there were 1,300 barrels inside shipping containers.

The chemicals had been loaded onto the ships from a port in Shanghai, China, Pirro said, adding that they were en route to Mexico to be used by the Sinaloa Cartel. The meth the cartel would have produced would have likely made its way into the U.S.

Pirro said that the seizure will put a dent in the drug trafficking organizations, though it may take them a while to recoup from the loss.

The Trump administration has been putting pressure on China for its role in the fentanyl epidemic in the U.S., which kills tens of thousands of Americans every year.

In a separate instance, the U.S. Treasury Department announced Wednesday that it is sanctioning Chinese chemical company Guangzhou Tengyue Chemical Co., Ltd. and two of the company’s representatives, Huang Xiaojun and Huang Zhanpeng, for manufacturing and coordinating shipments of illicit opioids and chemical agents to the United States.