Runaway schoolgirl Shamima Begum should be allowed to return to the UK "as a matter of urgency" to safeguard her unborn child, he family has said.
In a statement issued to ITV News, they said the revelation the 19-year-old is still alive came as a shock to them, and they urged the Government to help her return to Britain, four years after she travelled to Syria to Syria to join Islamic State.
"Given Shamima's four-year ordeal, we are concerned that her mental health has been affected by everything that she has seen and endured," they said.
"Now, we are faced with the situation of knowing that Shamima's two young children have died – children that we will never come to know as a family.
"This is the hardest of news to bear.
"The welfare of Shamima's unborn baby is of paramount concern to our family, and we will do everything within our power to protect that baby who is entirely blameless in these events."
Speaking to The Times at a refugee camp in northern Syria, Ms Begum said she would "do anything required just to be able to come home and live quietly with my child".
During the interview she admitted that she did not regret travelling to IS-controlled Syria, and asserted she is "not the same silly little 15-year-old schoolgirl who ran away from Bethnal Green four years ago".
The statement her family issued on Friday evening said they were shocked by her comments in the interview, but her words were those "of a girl who was groomed".
"We are also mindful that Shamima is currently in a camp surrounded by IS sympathisers and any comments by her could lead directly to danger to her and her child," they added.
Her family said her unborn child, who will be British, has "every right as a total innocent to have the chance to grow up in the peace and security of this home".
"We welcome an investigation in what she did while she was there under the principles of British justice and would request the British Government assist us in returning Shamima and her child to the UK as a matter of urgency," the statement said.
It came after the head of MI6 warned that Britons returning from Islamic State are likely to have acquired "potentially very dangerous" skills and connections.
Alex Younger, who did not comment specifically on the case of Ms Begum, said UK nationals have a "right" to come home but that public safety was the first priority.
Meanwhile, Home Secretary Sajid Javid warned he "will not hesitate" to prevent the return of Britons who travelled to join IS.
The head of Counter Terrorism Policing, Assistant Commissioner Neil Basu, said: "Anyone who returns from Syria or other conflict zones, having gone in support of any proscribed terrorist group – whether that's fighting for or against Daesh – or for any other illegal purposes, can expect to be investigated by the police.
"Any investigation is carried out with an open mind and based on the evidence available. This is to determine if individuals have committed any terrorist or other criminal offences, regardless their motivation, and to ensure that they do not pose a danger to the public or the UK's national security.
"There can be no hope of repatriation without these investigations taking place, and anyone who does return to the UK from conflict zones can, at best, expect to live under stringent limitations set out in the Terrorism Prevention and Investigation Measures (TPIM) Act.
"We as a society must learn that we can stop this from happening in the first place by trusting our Prevent strategy, reporting our concerns early and stopping people being radicalised, investigated and, most likely, criminalised by the poisonous rhetoric spewed by terrorist organisations of any ideology."
Mr Javid said those who left the UK to join IS were "full of hate for our country", while security minister Ben Wallace warned that runaways who now want to come back must realise that "actions have consequences".
Anthony Loyd, The Times correspondent who found Ms Begum, said she was a "15-year-old schoolgirl who made a terrible mistake... and we must do our best to rehabilitate her amongst our own people".
But her plea has been strongly rejected by others – including the brother of Alan Henning, the British aid worker beheaded by Jihadi John, who said she should "absolutely not" be allowed back.
Any hopes of a rescue mission by British officials were also swiftly quashed on Thursday as the Government ruled out an effort inside Syria to assist Ms Begum.
While refusing to comment on individual cases, Mr Wallace told the BBC: "I'm not putting at risk British people's lives to go and look for terrorists or former terrorists in a failed state.
"There's consular services elsewhere in the region and the strong message this Government has given for many years is that actions have consequences."
While no official operation to remove Ms Begum from Syria will be carried out, questions have been raised over whether Britain would be able to prevent Ms Begum's eventual return to the UK.
Former independent reviewer of terrorism legislation Lord Carlile told the BBC that if Ms Begum has not gained a second citizenship of another country, she will have to be allowed back to her homeland because under international law it is not possible for a person to be made "stateless".
Meanwhile, Richard Barrett, a former director of global counter-terrorism at MI6, suggested it would be "unreasonable" to expect the Syrian Defence Force to look after her indefinitely.
He also warned that summary execution is the "most likely outcome" for such captured foreign nationals who are handed over to Syrian or Iraqi authorities.