Pope Francis has fired Bishop Joseph E. Strickland of Tyler, Texas, one of his fiercest critics among conservative US Catholics, the Vatican said in a statement on Saturday.

It is very rare for a Roman Catholic bishop to be relieved of his duties. Typically, bishops in trouble with the Vatican are asked to resign before submitting their resignations, which are accepted by the Pope.

Popes take what are considered drastic steps when a bishop refuses a request to resign. Strickland is 65, 10 years shy of the normal retirement age for Catholic bishops.

Strickland, who has been bishop of the diocese since 2012 and is a frequent user of social media, tweeted earlier this year that he rejected “the Pope’s program that undermines the deposit of faith.”

The firing follows a Vatican investigation earlier this year into the administration of the Diocese of Tyler, which Catholic media said included how financial affairs were handled.

The release was announced simultaneously by the Vatican and the US Bishops’ Conference. Neither statement gave a specific reason for the dismissal. There was no immediate response from Strickland.

Francis appointed Bishop Joe Vazquez of Austin, Texas, as interim administrator of the diocese, the statement said.