WASHINGTON (AP) — The son of a fugitive Mexican drug kingpin pleaded not guilty Friday to federal drug charges during an appearance in U.S. District Court after his overnight extradition from Mexico.

Ruben Oseguera faces charges of conspiracy to distribute large quantities of cocaine and methamphetamine and use of a firearm in commission of a drug trafficking offense. If convicted, he faces at least 15 years in prison. He appeared in a beige jumpsuit Friday for a brief arraignment, looking slightly confused. He was represented by a public defender and communicated through an interpreter.

Oseguera is known as “El Menchito,” after his father, Nemesio Oseguera, alias “El Mencho,” Mencho being a common nickname for Nemesio. The younger Oseguera was born in California and holds dual U.S.-Mexican citizenship. He was arrested in 2015 on weapons possession and organized-crime charges, and had been fighting extradition.

The elder Oseguera is the leader of the Jalisco New Generation cartel. He remains a fugitive, and the U.S. government has offered $10 million for information leading to his arrest.

Government prosecutor Brett Reynolds told the court that Jalisco New Generation is considered by the U.S. government as “one of the largest, most dangerous drug cartels” and that Ruben Oseguera represents a “serious flight risk” and should remain in government custody.

Oseguera declined to make a case for his release and asked for a continuation of the hearing to give his family time to hire a personal lawyer. His detention status will be determined in a hearing Wednesday.

He was handed over to U.S. authorities Thursday after he lost a long legal fight against extradition, Mexico’s top security official, Alfonso Durazo, said Friday. The extradition raised fears his powerful gang may retaliate.

The Jalisco cartel is currently Mexico’s most violent and fastest-growing gang.

The U.S. Embassy issued a security alert saying “following previous high-profile security operations, criminal groups operating in Jalisco have responded by taking retaliatory actions including an increase in anti-government rhetoric (banners and internet threats) and blockades inside the city and on interstate highways.”

“On some occasions, these criminals have seized private vehicles and set them on fire,” according to the alert.

Durazo said officials were on the lookout for any reaction.

He said Mexico had tried to extradite Oseguera before but “in fact, the process was a long one because of several legal appeals” filed by his lawyers, the last of which was rejected this week.

Víctor Francisco Beltrán, Oseguera’s Mexican lawyer, said the extradition shouldn’t have happened, because the younger Oseguera still had pending appeals.

Jalisco New Generation has a reputation for battling with government agents. It brazenly shot down a Mexican military helicopter with a rocket launcher in 2015, prompting Mexican officials to declare an all-out offensive against the criminal group.