The Roman Catholic Diocese of Providence said a pastor has acknowledged that he sexually abused a minor more than 30 years ago and has resigned from two parishes in Woonsocket. The diocese said in a statement Monday that Monsignor John Allard was placed on administrative leave and has expressed remorse. State Police Major Michael Winquist said police received a letter from the diocese around Feb. 13 that outlined the allegations. Winquist said a boy who was one of Allard’s parishioners in Cranston was allegedly assaulted by the priest in 1981. The diocese said Allard served at Immaculate Conception in Cranston from 1975 to 1984.