Katie and Gemma had all their own clothes taken away

The Bray family

Gemma Bray, 15, and her 13-year-old sister Katie also had their clothes taken off them and were asked if they had been abused or were suicidal.

Their mother Yvonne Bray of Appledore, Devon, says their human rights were infringed by the authorities.

She was hospitalised with pneumonia during a trip to New York.

The Administration for Children's Services in New York has declined to comment on the matter.

I'm not guilty of anything other than getting ill in a country without family or friends

Yvonne Bray

"What should have been the trip of a lifetime turned out to be a complete disaster from start to finish," Ms Bray told BBC News.

"I was going to give the girls money for their Christmas, but with the exchange rate being so good, I decided to book the trip to New York.

"This was their Christmas present and it was totally ruined."

The family flew out to New York on 27 December. When Ms Bray began coughing later that day, she initially put it down to her asthma and the air conditioning on the flight.

The following night, she became more unwell with laboured breathing and was admitted to the Queen's Medical Centre in Harlem.

Yvonne Bray said she had now received a letter from social workers

But Ms Bray was told her daughters could not stay with her at the hospital as they were minors.

"A doctor told me they would make the arrangements, then a few hours later a social worker arrived and said they'd try to find a foster family for the girls," she said.

"Instead of that they were taken to a orphanage and subjected to the kind of treatment you wouldn't even expect criminals to go through."

The frightened teenagers had their clothes, including their underwear, removed and were issued with a uniform of T-shirt and jeans before being spilt up and given a medical examination.

"Being away from Mum when you are alone in New York in an strange place with people you don't know - it's just scary," said Katie.

You didn't know how long you'd be there or if Mum would get better

Katie Bray

"At first it was so shocking - it was as if it wasn't happening but then it hits you.

"You didn't know how long you'd be there or if Mum would get better."

Photographs were taken and the girls were told they would not be allowed to visit their mother in hospital.

When the duty social worker told Ms Bray her daughters could not leave the orphanage, she discharged herself from the hospital against medical advice.

She said: "I was so cross. I didn't sign anything saying they could be examined or interrogated - they even asked them if they had been raped.

"They had to shower in front of strangers. What they went through would be a breach of anyone's human rights, let alone two girls on holiday."

'It's disgraceful'

Ms Bray has now received a letter from the Administration for Children's Services (ACS) to say she is now being investigated.

"It's disgraceful, but I'm trying to totally dismiss this," Ms Bray said.

"It seems like a standard letter because the children have been entered into the child care system.

"I'm not guilty of anything other than getting ill in a country without family or friends."

A spokeswoman from ACS told BBC News it was an "entirely confidential matter" and the department would not comment.