Vatican City, July 1 (AP): Pope Francis declined today to renew the mandate of the Vatican's conservative doctrine chief, tapping a deputy instead to lead the powerful congregation that handles sex abuse cases and guarantees Catholic orthodoxy around the world.

In a short statement, the Vatican said Francis thanked Cardinal Gerhard Mueller for his service. Mueller's five-year term ends this weekend and he turns 70 in December. The normal retirement age for bishops is 75.

Francis could have kept him on, but declined to do so. The two have clashed over the pope's openness to allowing civilly re-married Catholics to receive Communion. Mueller has insisted they cannot, given church teaching on the indissolubility of marriage.

The Jesuit pope tapped the No. 2 in the Congregation for the Doctrine of the Faith, Jesuit Monsignor Luis Ladaria Ferrer, to succeed Mueller.

It was the second major shake-up this week, after Francis granted another Vatican hardliner, Cardinal George Pell, a leave of absence to return to his native Australia to face trial on sexual assault charges. Mueller and Pell were two most powerful cardinals in the Vatican, after the Vatican secretary of state, Cardinal Pietro Parolin, and their absences will likely create a power vacuum for the conservative wing in the Holy See hierarchy.

Emeritus Pope Benedict XVI had tapped Mueller to lead the congregation in 2012. Benedict had taken a hard line against clerical sex abuse during his time as prefect of the congregation himself, defrocking hundreds of priests accused of raping and molesting children.

It was also Benedict who insisted that bishops around the world send all cases of credibly accused priests to the congregation for processing.

During Mueller's tenure, the sex abuse caseload piled up as more and more victims came forward from Latin America, Europe and beyond. Last year, Francis confirmed there was a 2,000-case backlog.

Mueller's handling of the abuse portfolio came under fire from Marie Collins, an Irish survivor of abuse. Collins resigned from Francis's sex abuse advisory commission in March in frustration of what she said was the congregation's "unacceptable" resistance to accepting the commission's advice on how to better respond to victims.