A senior adviser to the Pope has said excommunication could be used to punish Mexican drug traffickers.
Cardinal Tarcisio Bertone, who is the Vatican secretary of state, said it was the church's severest form of rebuke.
Cardinal Bertone said the church was alarmed at what it called the disasters of drug-fuelled violence in Mexico, a largely Catholic nation.
The country's drug cartels have been responsible for thousands of deaths in the past few years.
Speaking ahead of a trip to Mexico, the cardinal said excommunication could be a possible punishment for the traffickers, who last year alone were blamed for more than 5,000 deaths.
Excommunication is the process that bars Catholics from receiving sacraments and participating in public worship.
Cardinal Bertone said it was a very harsh deterrent, that the church used only for the most serious of crimes.
But he accepted that such a course of action would probably have little effect on the traffickers.
"It touches only those who have some form of ecclesiastical conscience," he said.
The Catholic Church in Mexico has given its public support to government efforts to tackle the traffickers.
There are others, though, who suspect that some Catholic priests benefit directly or indirectly from money provided by the cartels, particularly in poorer areas of Mexico.
Cardinal Bertone said the church had a duty to fight the drug gangs.
"Their actions represent the most hypocritical and terrible way of murdering the dignity and personality of today's youth," he said.
By Duncan Kennedy
BBC News, Rome
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