The Mexican government has said the leader of the Zetas drug cartel was captured in an early-morning raid yesterday.
The arrest of Miguel Angel Trevino marks the biggest victory for President Enrique Pena Nieto in his fight against gang-led violence.
Marines arrested Mr Trevino after intercepting his pick-up truck with a helicopter a few kilometres from his home town of Nuevo Laredo on the US border.
"Not a single shot was fired," government spokesman Eduardo Sanchez told reporters.
The Zetas have been blamed for many of the worst atrocities in Mexico's struggle with drug gangs.
Mr Pena Nieto has pledged to restore peace to a country that has suffered more than 70,000 deaths to cartel violence since the start of 2007.
Mr Trevino, 40, was caught along with two associates following a months-long operation to track him down, Mr Sanchez said.
Authorities also seized more than $2m in cash and a cache of arms in the operation.
Mr Trevino's capture was the latest in a string of blows to hit the Zetas, whose previous leader was killed by marines in a gun battle in northern Mexico last year.
Among the crimes attributed to the Zetas is the massacre of dozens of migrants in northern Mexico in 2010, an arson attack on a Monterrey casino in 2011 and the dumping of 49 decapitated bodies near the same city last year.
Mr Pena Nieto came to office in December 2012 promising to improve security in a country increasingly worn down by the bloodshed under his predecessor Felipe Calderon.
The US State Department had offered a reward of up to $5m for information leading to Mr Trevino's capture.