MEXICO CITY — A 19-day army crackdown on the violent Zetas drug gang in northern Mexico has left 31 dead including a soldier and an alleged local gang leader, the defense ministry said Thursday.

More than 30 people were injured and 196 detained in the operation, which started on July 16 and saw the deployment of 4,000 soldiers and 23 planes, the ministry said in a statement.

Authorities also seized 1,217 weapons, three metric tons of marijuana and more than 500,000 dollars, it added.

It was one of the largest reported crackdowns on the Zetas, a violent drug gang founded by elite military deserters who were first hired by the Gulf cartel.

Authorities blame a split between the Gulf Cartel and Los Zetas for some of the most vicious drug-related violence in Mexico in recent years.

Soldiers detained Valdemar Quintanilla Soriano, the suspected number two financial operator of the Zetas, on Tuesday as part of the same crackdown in northern Coahuila state, the statement said.

The same day, Jorge Luis de la Pena Brizuela, head of the Zetas in the border city of Nuevo Laredo, was killed in a shootout and another local Zetas leader was arrested in San Luis Potosi, capital of the eponymous northern state.

More than 41,000 people have died in violence blamed on Mexico's drug cartels since the end of 2006, when President Felipe Calderon deployed some 50,000 troops to tackle organized crime.