Indian authorities say they have sealed a home run by Mother Teresa's religious order and charged a nun and one other person with baby trafficking.

The home in eastern India's Jharkhand state is run by Missionaries of Charity, the order set up by Mother Teresa in India, and provides shelter for pregnant unmarried women.

"They have said that at least five to six babies have been sold to childless couples," police officer Aman Kumar told Reuters in a phone interview.

"We are investigating to see how the operation was run and how many more children have been given away in the last few years."

An Indian couple claimed they paid 120,000 rupees ($2,354) to Anima Indwar, who worked at the shelter run by the Missionaries of Charity, said Mr Kumar.

The arrests of the nun and another worker on Tuesday and Wednesday followed the couple's complaint the charity worker had taken back the baby boy and kept their money.

Mr Kumar said the police were investigating three other complaints against Ms Indwar for allegedly selling children from the shelter.

Spokeswoman Sunita Kumar said the Missionaries of Charity was investigating.

"There was no question of selling any child as the Missionaries of Charity had stopped giving children for adoption three years ago," she said.

She said the charity had never taken money from parents while arranging adoptions in the past.

Mr Kumar said 100,000 rupees ($1,964) was recovered from the two who were arrested.

The Missionaries of Charity stopped organising adoptions in India in 2015, saying they disagreed with government rules that made it easier for single, divorced, and separated people to adopt children.

There have been a number of reports of babies and children being trafficked through charity-run homes and hospitals, which campaigners say is driven by a long waiting list for adoption.

The Nirmala Shishu Bhavan home, run by the Missionaries of Charity in Jharkhand state capital Ranchi, was required to inform authorities about all babies born there.

"They were selling more babies than what they were handing over to authorities," said Baidnath Kumar, a Ranchi-based child rights activist who had filed complaints against the home.

Mr Kujur said his organisation had directed that the credentials of every home run in the state should be checked.

"We hear that babies are being sold in other homes as well and are determined to put a stop to it," he said. (ABC News)

•Roman Catholic nuns are shown next to a photo of Mother Teresa at the Missionaries of Charity house in Kolkata, India.

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