KOLKATA, India - A nun in her 70s was gang-raped by a group of bandits Saturday when she tried to prevent them from robbing a Christian missionary school in eastern India, police said, the latest crime to focus attention on India's scourge of sexual violence.

The nun was hospitalized in serious condition after being attacked by seven or eight men at the Convent of Jesus and Mary School in Nadia district, 50 miles northeast of the West Bengal state capital of Kolkata, a police officer said.

The men escaped and police were searching for them, said the officer, who spoke on condition of anonymity because he was not authorized to talk to reporters.

The robbers bound the school security guards early Saturday and entered the room where the women were sleeping. They took one to another room when she tried to block their way and then raped her, the officer said.

The victim is the oldest nun at the school, he said.

The men escaped with some cash, a cellphone, a laptop computer, and a camera, all belonging to the school, the officer said. They also ransacked the school chapel and holy items, the Press Trust of India news agency cited the archbishop of Kolkata, Thomas D'Souza, as saying.

Scores of angry students, their parents, and teachers blocked a highway and railroad tracks for several hours, demanding swift police action leading to the arrest of the men.

Mamta Banerjee, the state's top elected official, strongly condemned the attack and ordered a high-level police investigation. D'Souza appealed to people to maintain peace and harmony.