"In assuring the entire community of his spiritual closeness, His Holiness commends the souls of those who have died to the loving mercy of almighty God and prays for the healing and consolation of the injured and bereaved," said a telegram signed by Cardinal Pietro Parolin, Vatican secretary of state, and issued on the pope's behalf.

The telegram was sent Jan. 2 to Archbishop Gregory M. Aymond of New Orleans.

According to law enforcement agencies, a U.S. Army veteran, apparently inspired by the Islamic State group, drove a pickup truck into a crowd of people celebrating the new year in New Orlean's famed French Quarter early Jan. 1 before he was killed in a shootout with police. In addition to the 15 people who died, some 30 other people were injured.

"This violent act is a sign of utter disrespect for human life," Archbishop Aymond said in a statement Jan. 1. "I join with others in the Roman Catholic Archdiocese of New Orleans in offering prayerful support to the victims' families. I give thanks for the heroic duty of hundreds of law enforcement and medical personnel in the face of such evil."

The attack came after a similar incident in Magdeburg, Germany, where five people were killed and more than 200 injured when a man drove into crowds at a Christmas market Dec. 20.

Rome increased security measures around the Vatican in preparation for the opening of the Holy Year and for the Christmas and New Year's holidays.