Cardinal Pietro Parolin said the Society of St. Pius X's ordination of four bishops in Écône on July 1 was "in itself a schismatic act" because it was carried out without papal mandate.
Six bishops involved in the unauthorized rite could face automatic excommunication, though Parolin said he did not know when or how the sanction would be formally addressed.
Pope Leo XIV had urged the group to "please turn back" before the ceremony, but the ordinations went ahead at the SSPX's Swiss headquarters.
Parolin said the deeper dispute remains SSPX's acceptance of the Second Vatican Council, which he called a milestone in Church history that must be accepted and implemented.
Despite calling the ordinations a serious wound to Church unity, Parolin said he still hopes dialogue with SSPX can resume and produce a solution.