Ivan Velazquez, also known as “Z-50”, was key leader of Zetas drug cartel, and had a reward of up to $2.3m on his head.

The Mexican navy has said it had captured one of the leaders of the Zetas drug cartel, a notoriously brutal gang reported to be breaking apart due to an internal feud.

The navy said on Wednesday it had caught the man it believed to be Zetas boss Ivan Velazquez in the central state of San Luis Potosi, in a boost to outgoing President Felipe Calderon’s efforts to crack down on the violent cartels.

The Zetas have perpetrated some of the most sickening acts of Mexico’s drug war and continued to expand even as rival gangs joined forces against them. They are now regarded as one of the two most powerful drug cartels in the country.

Velazquez is due to be paraded before the media on Thursday morning as is customary with such captures in Mexico.

The suspected gang leader surrendered to the navy in the city of San Luis Potosi without a shot being fired, an eyewitness told Reuters.

Known as “Z-50” or “El Taliban,” Velazquez has been one of the leading figures in the Zetas. Formed by a group of army deserters in the late 1990s, the gang acted as enforcers for the Gulf Cartel before splitting with their employers in 2010.

Longstanding rivalry between the Zetas’ top leader, Heriberto Lazcano, and his second-in-command Miguel Trevino has exploded into violence, raising fears the hostilities could bring a fresh wave of bloodletting.

Brutal menace

The Zetas boast 10,000-plus gunmen, and the prospect of them fighting for control of local trafficking networks and smuggling routes has alarmed security experts.

However, the split also brings benefits for the government, as members of the gang inform against former colleagues.

Earlier this week, Mexican news magazine, Proceso, reported that Velazquez had switched his allegiance to the Gulf Cartel due to a rupture with Trevino, citing messages posted online.

Velazquez is listed by the government as one of the country’s most-wanted drug kingpins. The Mexican government has offered a reward of up to $2.34m for information leading to his arrest.

Since 2009, more than 20 drug lords have been caught or killed. The most recent capture came two weeks ago, when the navy arrested Gulf Cartel head Jorge Costilla, alias “El Coss”.

Earlier on Wednesday, the navy announced the capture of 18 suspected Zetas in the northern state of Nuevo Leon.

How to contain the threat posed by the drug gangs is one of the main challenges facing Calderon’s successor Enrique Pena Nieto, who is due to take office on December 1.

About 60,000 people have been killed in drug-related violence during Calderon’s six-year term.

Clashes in south

In separate incident, Mexican authorities say troops have clashed with an armed group near a church in southern Mexico, leaving 11 people dead, including a soldier and one woman.

The Guerrero state prosecutor’s office says troops confronted the group in the town of Tepecoacuilco de Trujano, about 200km south of Mexico City.

It says state police found ten bodies in and around a chapel, in addition to the soldier who died in Wednesday’s shootout.

Officials say two civilians were wounded, who had apparently been kidnapped by the group.