Newly consecrated Bishops, from left, Pascal Schreiber, Michael Goldade, Michel Poinsinet de Sivry and Marc Hanappier, wearing their miters and holding their pastoral staffs, pray at the end of their consecration ceremony in a tent set up outside the Society of St. Pius X seminary in Econe, Switzerland, Wednesday. (AP Photo/Baz Ratner)

VATICAN CITY (AP) — The Vatican responded aggressively Thursday to a traditionalist group that consecrated bishops without the pope’s consent, declaring the Society of St. Pius X had formally broken with the Catholic Church. It excommunicated its bishops and priests, and warned its faithful that they too face the harshest sanctions in the church.

By declaring a schism and extending excommunications to potentially thousands of Catholics, the Vatican’s doctrine office went above and beyond the minimum sanctions foreseen by the church’s canon law to respond to the consecrations Wednesday of four new bishops.

The society, known by its acronym SSPX, celebrates the ancient Latin Mass and opposes the modernizing reforms of the Catholic Church, which it considers to be rife with heresies and errors. While a fringe movement on the Catholic right, the SSPX has been a thorn in the Vatican’s side for five decades because it claims to be even more Catholic than the Holy See.

During a ritual-filled, five-hour Mass on Wednesday at its seminary in Econe, Switzerland, the SSPX consecrated four new bishops in direct defiance of Leo, who had urged the group to hold off for the sake of church unity. An estimated 15,500 people and their children attended, a sign that the SSPX has plenty of supporters who came from around the world knowing full well they were defying Rome.

The harshness of the response suggested that after trying to negotiate with the SSPX, the Vatican under Pope Leo XIV had had enough.

In a decree, the Vatican excommunicated the four new bishops and the two existing SSPX bishops who participated in the ceremony. It declared the consecrations a “schismatic act” and that the society itself had created a schism, or intentional rupture with the church.

It declared SSPX priests — who number about 750 — to be schismatic, and therefore excommunicated, and invalidated the sacraments of confession and marriage that they administer. The Vatican warned the faithful to stop going to SSPX Masses, decreeing that “those who adhere formally” to the society are schismatic and excommunicated.

The Vatican said that applied to people who are members of the SSPX lay branch and those who “regularly attend” SSPX Masses and formally share its doctrinal positions. The sanctions don’t apply to Catholic faithful who attend SSPX Masses “just for liturgical or spiritual reasons” or those who go but accept the pope’s authority and teaching.

The SSPX doesn’t have an exact count but estimates around 400,000-600,000 people attend its Masses, meaning Thursday’s decree could potentially involve the excommunications of thousands of rank-and-file SSPX faithful.