There are unconfirmed reports that the baby son of Shamima Begum – the teenager who fled London to join the Islamic State group – has died, her family’s lawyer has said.
Tasnime Akunjee said he had “strong but unconfirmed reports” of the death of the baby, who was about two weeks old.
However, a spokesman for the US-backed Syrian Democratic Forces said the baby was alive and healthy.
BBC correspondent Quentin Sommerville said Ms Begum had gone to hospital.
He said she had been taken there under armed escort on Thursday.
Ms Begum, who left the UK in 2015, was found in a Syrian refugee camp in mid-February.
She gave birth shortly afterwards and said she wanted to return to the UK, but the Home Office stripped her of her British citizenship.
In a tweet on Friday, lawyer Mr Akunjee said the baby son was a British citizen.
A child born to a British parent before they are deprived of their citizenship would still be considered British.
But Mustafa Bali, the head of the press office for Kurdish-led alliance SDF, said the news that the baby had died was “fake”.
Ms Begum, 19, was a schoolgirl when she left Bethnal Green in east London in 2015. She married an IS fighter, a Dutch man called Yago Riedijk.
She was found by a journalist living in a refugee camp in northern Syria after reportedly leaving Baghuz – IS’s last stronghold.
Ms Begum said she had previously lost two other children and named her new son Jarrah after her firstborn.
In an interview with the BBC after the birth of Jarrah, she said she did not regret travelling to Syria – although she added that she did not agree with everything the IS group had done.
She also said that she never sought to be an IS “poster girl” and simply wished to raise her child quietly in the UK.
After Ms Begum was stripped of her citizenship, her family wrote to the home secretary to say they planned to challenge the decision and asked for the government’s assistance to bring her baby to the UK.
Earlier this week, Mr Akunjee tweeted a screenshot of the reply that they had received from the Home Office.
It told them that the possibility of bringing the baby to the UK was a matter for the Foreign and Commonwealth Office and that they would need permission from Ms Begum.
The FCO is obliged to consider requests for consular assistance, the letter added.
Home Secretary Sajid Javid previously said that the revocation of Ms Begum’s citizenship would not apply to her son, saying: “Children should not suffer, so if a parent does lose their British citizenship it does not affect the rights of their child.”