"This is the largest seizure of precursor chemicals used to manufacture methamphetamine in US history," US Attorney for the District of Columbia Jeanine Pirro told reporters at the Port of Houston in the southern state of Texas.

She spoke in a warehouse filled with plastic-wrapped blue barrels -- 13,000 of them, according to Pirro -- shipped from Shanghai on two separate vessels, and bound for laboratories of the Sinaloa Cartel in Mexico when they were seized "on the high seas" last week.

"Foreign law enforcement partners" assisted US personnel to consolidate the shipments in Panama and bring them to Houston, said Todd Lyons, acting director of US Immigration and Customs Enforcement (ICE).

The Trump administration's designation of the Sinaloa cartel as a foreign terrorist organization has given federal authorities the ability to track precursor chemicals before they reach US soil, Lyons said.

"Everyday, 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 and their citizens," Pirro said.

The chemicals would have been used to make 420,000 pounds of methamphetamine with a street value in Houston of $569 million, Pirro said.

The seizure was announced a day after Trump said US forces had attacked a drug-smuggling boat off Venezuela, killing 11 "narcoterrorists" in international waters.

The attack marked a major escalation of US action after Trump signed an executive order authorizing military action against drug cartels.

Secretary of State Marco Rubio, in Mexico for a meeting with President Claudio Sheinbaum on Wednesday, vowed the United States would ramp up strikes on cartels, but assured Mexico of respect for its sovereignty.

Also this week, the US Treasury Department sanctioned a Chinese chemical company, Guangzhou Tengyue, that it said was involved in the manufacture and sale of synthetic opioids to Americans.

Treasury's Office of Foreign Assets Control also sanctioned two individuals connected to the company, Huang Xiaojun and Huang Zhanpeng, alleging they were directly involved in shipping illicit drugs to the United States. The sanctions freeze any property or assets they have in the United States.

Drug overdoses are the leading cause of death for Americans aged 18 to 45, according to US officials, who say companies in China are the main source of chemicals use to make illicit drugs that enter the United States.