A top drug-trafficking accomplice of Joaquin 'El Chapo' Guzman was detained in Mexico on Wednesday, shortly after he was returned from the United States after completing a prison sentence for distributing cocaine.

Hector 'El Guero' Palma was a former partner of Guzman, the head of the powerful Sinaloa cartel who is now fighting extradition to the United States from a Mexican prison.

Palma was rearrested by officials on his repatriation to Matamoros, a town directly across the US border, although it is unclear what charges he faces.

In the absence of Guzman, Mexican officials appear to be increasingly wary of Palma, given his ties to the Sinaloa cartel.

Palma, who first served five years in Mexico's maximum-security Puente Grande prison, was extradited to the United States in 2007. He played a key role in the cartel, which became famous in the 1980s for trafficking cocaine from Colombia in association with the late Colombian drug lord Pablo Escobar.

Palma served most of a 16-year sentence, which was reduced because of good behaviour, said Kristi Rodriguez, from the US penitentiary in Atwater, California.