VATICAN CITY — Pope Francis has voiced alarm at the “hemorrhaging” of nuns and priests in Italy and Europe, saying God only knows how many seminaries, monasteries, convents and churches will close because fewer people are being called to lives of religious service.

Francis told Italy’s bishops Monday that he was concerned about the “crisis of vocations” in a region of the world that once was one of the biggest sources of Catholic missionaries. He said Italy and Europe were entering a period of “vocational sterility” to which he wasn’t sure a solution exists.

The number of Catholic priests worldwide declined by 136 to 415,656 in 2015, the last year for which data is available. But according to Vatican statistics, the decrease was greatest in Europe, where there were 2,502 fewer priests compared to 2014. The number was offset by increases in priestly vocations in Africa and Asia, where the church as a whole is growing. During the same period, the number of baptized Catholics rose globally from 1.27 million to nearly 1.29 million, meaning the ratio of Catholics to the priests available to minister to them is growing

In a speech to an annual assembly of the Italian bishops conference Monday, Francis blamed the priest shortage on factors such as demographic changes, scandals in the church and cultural trends that dissuade young people from making lifelong commitments and make them value instead the “dictatorship of money.”

“How many seminaries, churches, monasteries and convents will be closed in the next few years?” he asked. “God only knows.”

Francis has already said the church must study whether it’s possible to ordain married men of proven faith, so-called “viri probati,” to minister in remote communities facing priest shortages.

The “viri probati” proposal has been around for decades, but drawn fresh attention under history’s first Latin American pope thanks in part to his appreciation of the challenges facing the church in places like Brazil, a huge Catholic country with an acute shortage of priests.

The proposal is likely to be discussed at a 2019 meeting of the world’s bishops to discuss the Amazon region, where the church counts around one priest for every 10,000 Catholics.