Pope Francis called on the world's Catholic cardinals, many of whom live in Rome and lead Vatican offices, to pursue a "zero deficit" agenda to improve the Vatican's use of its economic assets. The pontiff did not offer many specifics in a letter published by the Vatican on Friday,

"Additional effort is now needed on everyone's part so that a 'zero deficit' may not only be a theoretically, but effectively achievable goal."

In his first general audience since returning from the longest international trip of his pontificate, the pope expressed gratitude to God for his experiences.

Pope Francis has written to the College of Cardinals of the Catholic Church calling on them to step up efforts to cut costs as part of the reform of the Roman Curia launched a decade ago. "The past years have shown that the requests for reform,