NEW DELHI — A nun in her 70s was raped during the robbery of a convent school in West Bengal before dawn on Saturday, police and church officials said.

There were contradictory accounts in the hours after the attack, with some Indian news outlets describing the attack as a gang rape. Angry crowds, including some convent students, blockaded a railway line and a highway near the site of the crime, some 40 miles north of Kolkata.

Thomas D’Souza, the Catholic archbishop of Kolkata, said in a telephone interview that one man had raped the nun. He said six men armed with knives had broken into the Convent of Jesus and Mary in Ranaghat and “ransacked the place,” taking away whatever cash they could find.

He said the robbers tied up the security guard, then forced their way into the convent, where one of them raped the nun. He said other nuns were tied to chairs at the time.