MEXICO CITY • Pope Francis has admonished Mexico's political and religious leaders to take on drug violence, calling for "true justice" and "prophetic courage" against the scourge afflicting the country.

The Argentine-born pontiff used his visit at the National Palace and the capital's cathedral to send tough messages to the country's elite on the first full day of a cross-country tour of some of Mexico's hot spots.

At the palace on Saturday, with President Enrique Pena Nieto by his side in a patio packed with lawmakers and government officials, Pope Francis said political leaders have a duty to give "true justice" and "effective security" to Mexicans.

"Experience teaches us that each time we seek the path of privileges or benefits for a few to the detriment of the good of all... society becomes a fertile soil for corruption, drug trade, exclusion of different cultures, violence and also human trafficking, kidnapping and death," he said.

It was the kind of message that many ordinary Mexicans, fed up with a decade of drug violence that has left more than 100,000 dead or missing, were hoping for.

Mexico was reminded of its troubles on the eve of the Pope's arrival, when 49 inmates were killed in a prison brawl between rival groups in the north of the country.

Thousands of Catholic faithful who stood outside the National Palace in the historic Zocalo square broke into cheers at the Argentine pontiff's words.

"The Pope put the government to shame with everything that he said. Let's see if Mr Pena Nieto does the right thing," said Mr Ramiro Sosa, a 56-year-old shopkeeper from the crime-ridden eastern state of Veracruz.

The Mexican president gave Pope Francis a red-carpet welcome at the ornate palace, making him the first pope to visit the seat of governments that were militantly secular throughout the 20th century.

While Mexico is the world's second most populous Catholic country after Brazil, diplomatic relations with the Vatican were restored only in 1992.

The Pope also visited the capital's cathedral next door, where he called on Mexican bishops to combat drug trafficking with "prophetic courage".

"I urge you not to underestimate the moral and antisocial challenge which the drug trade represents for Mexican society as a whole, as well as for the Church," he said.

AGENCE FRANCE-PRESSE