VATICAN CITY (CNS) -- As the death toll rose from the massive tornado that struck near Oklahoma City May 20, Pope Francis offered a special prayer for the victims during his early morning Mass May 21 and later offered his condolences through his Twitter account.

Bishop Mulvey calls for aide to victims of storm Bishop Wm. Michael Mulvey, Bishop of Corpus Christi, joins Pope Francis in offering his prayers for the all those affected by the deadly and destructive tornados that struck in the Archdiocese of Oklahoma City. In a special communication to all parishes and missions of the diocese, Bishop Mulvey approved and encouraged a Special Collection to be taken up in all Churches either the weekend of Sunday May 26 or Sunday June 2 for the victims of the tornado that devastated Moore, Oklahoma.

"Let us pray for the victims -- at least 50 of them -- and the missing, especially the children, struck by the violent tornado that hit Oklahoma City yesterday. Hear us, O Lord," the pope said during the prayers of the faithful.

The tornado touched down at about 3 p.m. local time in Oklahoma and reportedly stayed on the ground for more than 40 minutes, leaving a 20-mile path of death and destruction. By midday Rome time May 21, news reports were saying at least 91 people, including 20 children, died. Two elementary schools were struck by the tornado.

A few hours after the Mass, Pope Francis also used his @Pontifex Twitter account to express his concern for the Oklahoma victims and survivors.

"I am close to the families of all who died in the Oklahoma tornado, especially those who lost young children. Join me in praying for them," he told the 2.5 million people who follow his English-language Twitter account and the 2.4 million who follow his Spanish-language account.