Pope Francis has dismissed Bishop Joseph E. Strickland of Tyler, Texas, one of his fiercest critics among U.S. Catholic conservatives, a Vatican statement said on Saturday.

It is very rare for a Roman Catholic bishop to be relieved of his duties outright. Usually bishops in trouble with the Vatican are asked to resign before submitting a resignation, which the pope accepts.

Popes make such moves, considered drastic, when a bishop refuses a request to resign. Strickland is 65, 10 years shy of the usual retirement age for bishops.   

Strickland, a prolific user of social media who had been bishop of the diocese since 2012, tweeted earlier this year that he rejected the pope's "program undermining the Deposit of Faith".

The dismissal followed a Vatican investigation earlier this year into the administration of the Tyler diocese, which Catholic media reports said included a review of his handling of financial affairs.

The dismissal was announced simultaneously by the Vatican and the U.S. Bishops Conference. Neither statement gave a reason. There was no immediate response from Strickland.

Francis named the bishop of Austin, Texas, Joe Vasquez, as the interim administrator of the diocese, the statement said.