Bangladesh has denied Islamic State schoolgirl Shamima Begum has dual nationality and said there is "no question of her being allowed" into the country.
In a statement on Wednesday, the country's ministry of foreign affairs said Ms Begum was not a Bangladeshi citizen and had never even visited the state.
But Bangladesh's government said it was "deeply concerned" that the 19-year-old had been "erroneously identified as a holder of dual citizenship".
"She is a British citizen by birth and has never applied for dual nationality with Bangladesh," the statement read.
"It may also be mentioned that she never visited Bangladesh in the past despite her parental lineage. So, there is no question of her being allowed to enter into Bangladesh."
As ITV News Security Editor Rohit Kachroo showed her a copy of the letter confirming the decision at the Syria refugee camp where she is being held, she said: "I'm a bit shocked... It's a bit unjust on me and my son."
The teenager, who gave birth to her baby boy on Sunday, said she had not been informed of the decision as she received the letter.
"I don't know what to say," she said. "I am not that shocked but I am a bit shocked. It’s a bit upsetting and frustrating. I feel like it’s a bit unjust on me and my son."
She added: "It’s kind of heart-breaking to read. My family made it sound like it would be a lot easier for me to come back to the UK when I was speaking to them in Baghouz. It’s kind of hard to swallow."
Referring to other returnees handled by the government, she said: "I heard that other people are being sent back to Britain so I don’t know why my case is any different to other people, or is it just because I was on the news four years ago?"
She said she may explore a potential citizenship route through her Dutch husband.
"Another option I might try with my family is my husband is from Holland and he has family in Holland.
"Maybe I can ask for citizenship in Holland. If he gets sent back to prison in Holland I can just wait for him while he is in prison."
Asked if she had a message or request for the home secretary, she told ITV News: "To maybe review my case again and have a bit more sympathy for me and understanding.
"Give me a reason why they see me as a threat to the UK."
The copy of the Home Office letter handed to her said: "Please find enclosed papers that relate to a decision taken by the Home Secretary, to deprive your daughter, Shamima Begum, of her British citizenship.
"In light of the circumstances of your daughter, the notice of the Home Secretary's decision has been served of file today (19th February), and the order removing her British citizenship has subsequently been made."
The letter went on to urge Ms Begum's family to make her aware of the decision and added that she had a right to appeal.
Addressing the House of Commons on Wednesday, Mr Javid announced: "There must be consequences for those who back terror."
Asked if she had a message for her family, Ms Begum said: "I want to apologise a lot for what I've put them through but right now I really need their help to bring me back. I can't stay here. I can't raise my son in this camp."
ITV News also asked her is she was aware of the devastation she has caused her family and why she ignored their pleas to come home.
"I saw on the internet the news and stuff and asking for me to come back."
She said she ignored the pleas "because I thought I was doing the right thing by being a part of Islamic State and that they were wrong for staying in the UK, not wanting to come with me".
Asked if she regretted ruining their lives she said: "Yeah. I've seen the impact it's had on them after I spoke to them. But after a while they got over it and the guilt kind of went away.
"And they just forgot about it. They slowly got over it and they had to accept that I came, they had to accept the decision I made."
Ms Begum and two school friends from Bethnal Green fled the UK via Turkey in 2015, where they made their way to Syria and were married off to Islamic State fighters.
Speaking to ITV News on Monday, the teenager insisted she was "not a threat" to the UK, despite having insisted she did not regret joining IS.
"I'm a 19-year-old girl with a newborn baby," she said..
"I don't have any weapons; I don't want to hurt anyone even if I did have weapons."