Cuba has arrested an alleged Chinese fentanyl kingpin who escaped custody in Mexico in July and is also wanted by the US, Mexican security sources told AFP on Wednesday.

Zhi Dong Zhang, known by the alias “Brother Wang” and with alleged ties to Mexico’s Sinaloa and Jalisco New Generation drug cartels, will remain in Cuba awaiting a decision on his possible extradition, the sources added.

Zhang escaped from house arrest in Mexico earlier this year while awaiting extradition to the US, where a warrant has been issued for his arrest on money laundering charges.

Zhi Dong Zhang is considered “a major international money laundering operator” responsible for “establishing connections with other cartels for the transfer of fentanyl from China to Central America, South America, Europe, and the United States,” Omar Garcia Harfuch, Mexico’s security secretary, said last year.

Washington under Donald Trump has been applying pressure on Mexico and China to curb drug trafficking, particularly of fentanyl: the powerful painkiller behind an overdose epidemic in the US.

Fentanyl 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 like oxycodone as a cause of overdoses in the US.

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

Communist Cuba has not officially commented on the reported arrest.