|Valencia is thought to run drug trafficking routes through Panama, the Dominican Republic and the US [Reuters]
Mexican police have arrested Eduardo "El Profe" Valencia, an alleged leader of the Zetas drug gang in the state of Hidalgo.
Valencia is believed to head drug trafficking operations that stretch from Panama and the Dominican Republic to the US.
A regional police chief said the arrest was the first time a Zetas leader of Valencia's stature had been taken into custody.
"This is the first time we found someone inside Los Zetas organisation who handled large amounts of drugs from Mexico to the US," said Luis Cardenas at a presentation of the detainee in Mexico City.
"This route, from the Dominican Republic and Panama is used by sea to try to smuggle drugs. Therefore we have hit on the negotiator responsible for the deals from those countries to Mexico."
Rival hitmen from the Gulf cartel and its former armed wing, the Zetas, have been fighting over lucrative smuggling routes into the US.
The gangs have targeted public officials, police officers and journalists who stand in their way.
Felipe Calderon, the Mexican president, has blamed a surge in violence around Monterrey and in Tamaulipas in northern Mexico on the split between the Gulf and the Zetas, but faces increasing pressure to calm the killings.
More than 31,000 people have been killed across Mexico since December 2006, when Calderon took office and launched his army-led crackdown.
Several mayors and other elected officials have been targeted by drug gangs in recent months.