A day after President Joe Biden spoke with Mexico's President Andres Manuel Lopez Obrador, the US has sanctioned Sinaloa Cartel leaders, including the notorious drug lord Joaquin "El Chapo" Guzman Loera's son, over fentanyl trafficking.

The Sinaloa Cartel, one of Mexico's most powerful drug cartels, is reportedly the leading trafficker of fentanyl to the US. 

According to the Associated Press, these sanctions were designated by the US Treasury Department on Tuesday to one of El Chapo's sons, Los Chapitos member Joaquin Guzman Lopez as well as three other Sinaloa Cartel leaders and two business firms based in Mexico.

The sanctions mean that the named individuals' and firms' American-owned assets and bank accounts will be frozen. American citizens are also banned from dealing with them.

The sanctions are meant to financially hurt the Mexican drug cartel, as the group also operates in the US. The sanctioned firms are a chemical and lab equipment company based in Culiacan in Mexico's Sinaloa state and a real estate business in the same city.

In a phone conversation, Lopez Obrador reportedly talked with Biden about immigration, arms trafficking, and the fentanyl crisis.

READ NEXT: Mexico: Warring Cartels Block Roads Near US Border

Aside From El Chapo's Son, 3 Other Sinaloa Cartel Leaders Also Sanctioned by the US

While El Chapo's son was the biggest name in the list of people and companies sanctioned by the US government, three other Sinaloa Cartel leaders have also been named.

They were Raymundo Perez Uribe, Saul Paez Lopez, and Mario Esteban Ogazon Sedano, who were marked as "designated" by the US Department of the Treasury's Office of Foreign Assets Control (OFAC), which means their assets held in US financial institutions were frozen and blocked.

According to CBS News, Perez Uribe leads a supplier network that the Sinaloa Cartel uses to obtain the chemicals used to create illegal narcotics.

On the other hand, Paez Lopez is reportedly responsible for coordinating drug shipments for members of the cartel's Los Chapitos faction.

Ogazon Sedano is the one responsible for buying the chemicals needed to make the drugs and operating illegal drug factories.

The two Mexican companies were sanctioned over their "involvement" with members and associates of the Sinaloa Cartel.

The cartel, which El Chapo founded in the 1980s, has been operating in the US and Mexico for decades. It is accused of being responsible for the largest amount of illegal fentanyl trafficked into the US.

The Sinaloa Cartel usually does this by exporting chemicals from China before using these chemicals to create illegal drugs in clandestine labs across Mexico.

They then employ drug mules and various methods to smuggle narcotics across the US.-Mexico border.

El Chapo's Sons, Known as Los Chapitos, Deny Being Leaders of the Sinaloa Cartel

The four sons of ex-Sinaloa Cartel boss El Chapo, collectively known as "Los Chapitos," have denied allegations that they were major drug traffickers flooding the US with fentanyl.

In a letter published by the Mexican news outlet Milenio earlier this month, El Chapo's sons wrote: "We have never produced, manufactured or marketed fentanyl or any of its derivatives." 

The letter was sent to Milenio by Jose Refugio Rodriguez, who confirmed to Reuters that he is a lawyer of the Guzman family.

In the letter, the Los Chapitos also denied being the leaders of the Sinaloa Cartel, saying they were just victims of an international misinformation campaign by firms, the media, and public figures that have painted them to be notorious drug traffickers.

"We are not the head of the Sinaloa Cartel nor are we interested in being... We are victims of persecution and have been made into scapegoats," they wrote.

The letter of Los Chapitos was a response to last month's press conference in Washington, where senior US officials said the Sinaloa Cartel was the main supplier of illegal fentanyl to the US.

The officials particularly blamed the Los Chapitos of the Sinaloa Cartel for worsening the opioid addiction epidemic in the US.

El Chapo's sons, namely Ovidio Guzman Lopez, Joaquin Guzman Lopez, Ivan Archivaldo Guzman Salazar, and Jesus Alfredo Guzman Salazar, are the Los Chapitos, who had reportedly assumed leadership roles in the Sinaloa Cartel after their father was arrested and extradited to the US.

Last month, the US Department of Justice charged 28 members and leaders of the Sinaloa Cartel, including Los Chapitos. The indictment charged El Chapo's sons with large-scale drug trafficking, money laundering, and "violent crimes." 

Only three of the Los Chapitos remain at large as Ovidio Guzman was already arrested last January 5 by Mexican authorities in Mexico's Sinaloa state. He remains detained in Mexico pending extradition proceedings to the U.S.

READ MORE: Los Chapitos, Among 28 Sinaloa Cartel Members Charged by US Government

This article is owned by Latin Post.

Written by: Rick Martin

WATCH: Sinaloa Princes: El Chapo's Sons Embrace the Cartel - From Reuters