Zhi Dong Zhang -- known as "Brother Wang" -- escaped house arrest in Mexico in July, and was transferred into US custody, according to Mexican Security Secretary Omar Garcia Harfuch.

He is alleged to have worked closely with Mexico's Sinaloa and Jalisco New Generation drug cartels, designated "foreign terrorist organizations" by Washington.

The Cuban government said that "after a formal request for extradition," the alleged traffickers was handed over to Mexican authorities.

Neither Mexico nor Havana has specified whether Zhang was transferred to the United States via Mexican soil, or if he was transported directly from Cuba.

Zhi Dong Zhang is considered "a major international money laundering operator," Garcia said last year.

The trafficker was responsible for "establishing connections with other cartels for the transfer of fentanyl from China to Central America, South America, Europe, and the United States," he added.

Since President Donald Trump returned to the White House in January, Washington has been applying pressure on Mexico and China to curb drug trafficking, particularly of fentanyl.

The powerful painkiller is a synthetic opioid that is 50 times more powerful than heroin and much easier and cheaper to produce.

It has largely replaced heroin and prescription opioids such as oxycodone as a cause of overdoses in the United States.

President Claudia Sheinbaum's government has ramped up drug seizures under tariff pressure from Trump, who has threatened further punitive measures unless the problem is solved.

Although Mexico has been the main source of fentanyl sold in the United States, Washington has increasingly focused its attention on China-based suppliers of precursor ingredients.