PHILADELPHIA — A Catholic priest accused of collecting thousands of child pornography images while serving overseas and then bringing them with him when he returned to the United States is now facing federal charges, authorities announced Thursday.

Father William McCandless, 56, of Wilmington, Delaware, pleaded not guilty to the counts during an initial court appearance in Philadelphia. He is charged with possessing child porn for importation into the Unites States, transporting child porn in interstate and foreign commerce and attempting to access with intent to view child porn.

McCandless was placed on home detention with electronic monitoring and was ordered to surrender his passport because he has frequently traveled overseas and has numerous contacts abroad. He is a member of the Wilmington-based religious order Oblates de St. Francis De Sales.

Federal prosecutors in the Eastern District of Pennsylvania said McCandless amassed his collection while serving for several years in Monaco, noting it included items that can be described “as the torture of very young children.”

McCandless’ attorney, John Waldron, noted that despite knowing about the investigation for more than three years, his client did not try to evade the likely charges.