An online “Rosary for Peace in Ukraine” organized by Archbishop Salvatore Cordileone of San Francisco was interrupted by an apparent cyberattack on March 2.

The web site of the San Francisco archdiocese was temporarily disabled by a huge volume of traffic. Archdiocesan officials suspect that they were the victims of a scheme known as a “distributed denial of service” attack, in which multiple computers are exploited to flood a site with traffic, causing a breakdown.

Archdiocesan officials were not able to pinpoint the source of the thousands of requests for access. The FBI has been asked to investigate.