MEXICO CITY (Reuters) - Mexican Marines said on Tuesday initial forensic tests confirmed they have killed the leader of the brutal Zetas drug cartel, one of Mexico's most wanted men.

The Marines said fingerprint tests in a database confirmed that Heriberto Lazcano had been killed in a firefight with marines in the northern state of Coahuila on Sunday afternoon.

Lazcano, alias "The Executioner," is the most powerful drug kingpin to fall in President Felipe Calderon's military offensive against the gangs.

The Zetas, considered one of the two most powerful drug gangs in Mexico, have perpetrated some of the most violent acts in the country's drug war that has killed about 60,000 people during Calderon's term.

(Reporting by Mexico Newsroom; Writing by Tim Gaynor; Editing by Doina Chiacu)