Upon landing on the tarmac, agents from HSI, along with the FBI arrested “El Mayo” and Guzman.

The HSI official tells ABC News the operation had been planned “for months.”

They were placed in handcuffs by FBI agents during an operation culminating at an airstrip not far from El Paso.

“The arrest of Ismael Zambada García, better known as ‘El Mayo,’ one of the alleged founders and leaders of the Sinaloa Cartel, strikes at the heart of the cartel that is responsible for the majority of drugs, including fentanyl and methamphetamine, killing Americans from coast to coast. El Mayo is one of DEA’s most wanted fugitives and he is in custody tonight and will soon face justice in a U.S. court of law,” said Drug Enforcement Administration Administrator Anne Milgram.

“Joaquin Guzman Lopez, another alleged leader of the Sinaloa Cartel, and the son of ‘El Chapo,’ was also arrested today — his arrest is another enormous blow to the Sinaloa Cartel. In 2017, he and his brothers, the Chapitos, allegedly took control of the Sinaloa Cartel after El Chapo was extradited to the United States. DEA will continue to seek justice for any American life that is lost and will work tirelessly to prevent more needless deaths and pursue those that are responsible,” Milgram said.

Mexican President Andres Manuel Lopez Obrador called the arrests a “breakthrough” in the fight against the drug crisis impacting the U.S. in comments on Friday.

The Mexican government said was not aware that the two were going to be extradited to the U.S. to be arrested, Mexican authorities said during a press briefing on Friday.

The Mexican government received a phone call from the U.S. Embassy Thursday afternoon informing them the two were in custody in El Paso, the authorities said. The Mexican government has asked U.S. officials for pictures of the two men to confirm the information.

According to the flight plan, the private plane that was used to transport the two men traveled from Hermosillo, Sonora, to Santa Teresa, New Mexico, Mexican authorities said.

The U.S. government had offered a $15 million reward for information leading to the arrest and/or conviction of Zambada.

“Too many of our citizens have lost their lives to the scourge of fentanyl,” President Joe Biden said in a statement Friday morning. “Too many families have been broken and are suffering because of this destructive drug. My Administration will continue doing everything we can to hold deadly drug traffickers to account and to save American lives.”

Guzman Lopez’s brother, Ovidio Guzman Lopez, was charged last year with two dozen others as part of a crackdown targeting a global drug trafficking network run through Mexico’s Sinaloa cartel. According to the charges, the cartel used precursor chemicals shipped from China to fuel the fentanyl crisis plaguing the U.S.

Ovidio Guzman Lopez had been wanted by U.S. authorities since 2019 and was captured by Mexican armed forces in January 2023 in a small town just outside the city of Culiacán, the capital of the Mexican state of Sinaloa.

He was captured in an overnight raid that had been in the works for more than six months, officials said at the time. The arrest followed an infamous incident in 2019, in which authorities briefly detained Guzman Lopez at a home in Culiacán, before word spread and heavily armed gunmen flooded the city. Massive shootouts occurred between cartel members and Mexican armed forces around the city. Mexican President Andrés Manuel López Obrador ordered Guzman Lopez released in order to avoid more bloodshed.

Their father is serving a life sentence in the U.S. after being convicted in 2019 of conducting a continuing criminal enterprise, including large-scale narcotics violations and a murder conspiracy, drug trafficking conspiracies, unlawful use of a firearm and a money laundering conspiracy.