Authorities said Thursday that they had arrested the son of one of Mexico's top drug lords, saying he had become a high-level operator of a powerful trafficking group in the northwestern state of Sinaloa.

Vicente Zambada, 33, was detained Wednesday in a well-to-do area of Mexico City during an operation by the army and federal agents. He is the son of Ismael Zambada, an alleged drug kingpin in Sinaloa.

Troops and agents moved in after reports of armed men in the Lomas del Pedregal section, the army said. Five other suspects, described as Vicente Zambada's bodyguards, were also taken into custody.

Authorities described the arrest as an important blow against the alliance of Sinaloa-based traffickers headed by Joaquin "El Chapo" Guzman Loera, who is Mexico's most-wanted fugitive.

"With the arrest of Vicente Zambada Niebla, 'El Vicentillo,' the Guzman Loera organization's ability to operate and move drugs is significantly affected," the military said in a statement. The army said Zambada had ordered the killings of police and rivals.

Officials said Zambada had been designated by his father to oversee operations, logistics and security, putting him among the top leaders of Guzman's group, the so-called Sinaloa cartel.

In that capacity, Zambada was said to have replaced Alfredo Beltran Leyva, who was arrested early last year.

The Beltran Leyva wing later broke from the rest of the Sinaloa alliance, resulting in months of internecine violence that left nearly 1,000 people dead statewide last year. The killing has tapered off recently amid reports of a truce.

Vicente Zambada is the latest member of the family captured during President Felipe Calderon's 2-year-old crackdown on drug traffickers.

In October, police arrested Ismael Zambada's brother, Jesus, who allegedly headed the group's operations in central Mexico. Authorities said he oversaw smuggling of cocaine and chemical ingredients for making methamphetamine.

The army-led offensive has roiled Mexico's drug gangs, stoking turf fights that have killed more than 7,000 people in the last 15 months. The crackdown has produced a number of high-profile arrests and major seizures of drugs, money and weapons.

During the arrest of Vicente Zambada, authorities seized three AR-15 rifles, three .38 Super pistols, three cars and nearly $5,000 in Mexican pesos and U.S. dollars.

ken.ellingwood@latimes.com