VATICAN CITY — Pope Francis is once again flexing his papal muscle by seeking to keep tabs on his cardinals who live in Rome.

Francis asked the head of the College of Cardinals to remind his fellow Rome-based princes that they must inform him when they leave town and where they’re going.

It wasn’t known if there was a particular cardinal whose activities irked the pope, but some of his more conservative critics have delivered speeches and lectures abroad that have questioned Francis’ pastoral line, particularly concerning his divisive opening to letting civilly remarried Catholics receive the Sacraments.

Cardinal Angelo Sodano reminded his confreres in a May 31 letter that there is a “noble tradition” of cardinals informing the pope of their whereabouts. He asked that they revive it, particularly when away from Rome for long periods.

Asked about the letter, Vatican spokesman Greg Burke said merely that it was a good and “long-standing tradition.”

Francis’ request comes on the heels of an extraordinary display of papal power last week, when he ordered all the priests of the Nigerian diocese of Ahiara to write him a letter within 30 days pledging their obedience. Failure to do so, he warned, would result in suspension.

The ultimatum stemmed from the refusal of Ahiara’s priests to accept the 2012 appointment of a new bishop.

The most striking display of Francis’ papal power came late last year, when he took over the Knights of Malta lay religious order. Francis intervened in the sovereign order during a governance crisis, forcing the ouster of its leader and naming a top Vatican official to help oversee the election of a new top knight and the revision of the knights’ constitutions.

Francis has prided himself on the broad consultation and discernment process he engages in before making decisions that is typical of a Jesuit superior. But like any good Jesuit, he is also decisive and knows how to wield his authority.

Ironically, Francis’ latest display of papal muscle comes as he and his cardinal advisers wrapped up another round of consultations about decentralizing authority from the Holy See to local churches.