The family of Shamima Begum, a London teenager who joined ISIS in Syria in 2015, said Friday it would challenge the British governments decision to revoke her citizenship. A letter to interior minister Sajid Javid written by Begums sister Renu on behalf of her family also called on the government to help bring her newborn son to Britain. The fate of the 19-year-old has triggered fierce debate in Britain, with the government telling her family this week that it was revoking her citizenship. Begum was 15 when she traveled to Syria but now wants to come home. "We hope you understand our position in this respect and why we must, therefore, assist Shamima in challenging your decision to take away the one thing that is her only hope at rehabilitation, her British citizenship," the familys letter said. Renu Begums letter also asked Javid to help "in bringing my nephew home to us". It said Shamima Begums status would now be a matter for British courts to decide. International law prevents a government from rendering a person stateless, but Britain reportedly believes that Begum also has Bangladeshi citizenship due to her parents, although she was born in Britain. The Bangladeshi government said there was "no question" of her being allowed to enter. Begums baby was born before she was told of the decision to revoke her citizenship, and is therefore British and has a right to return. The teenager said she was "shocked" by Britains decision, saying "if you take that away from me, I dont have anything. I dont think they are allowed to do that." She has mentioned the possibility of applying for citizenship in the Netherlands because her husband, an ISIS militant believed to be held by Kurdish forces in Syria, is a Dutch national. Public sentiment hardened against Begum after she showed little remorse in initial interviews from the refugee camp. Her family said on Friday they were "shocked and appalled" at the "vile comments" she made in the media. "I have watched Shamima on our televisions open her mouth and set fire to our nations emotions," said her sisters letter. "These are not representative of British values, and my family entirely reject the comments she has made, but... we as her family cannot simply abandon her." The family argued that it made "every fathomable effort" to prevent her from joining ISIS, which it called a "murderous and misogynistic cult". With ISIS crumbling, many European countries are now having to confront whether to bring back its citizens who traveled to join the group and prosecute them at home, or bar them from entry over security concerns. Some 400 people who joined ISIS in the early stages of the Syria conflict have since returned to Britain and around 40 of them have been prosecuted. There are believed to be around 10 British women who traveled to support ISIS who are now refugees in Syria. Opposition Labor Party leader Jeremy Corbyn said on Tuesday that Begum should be allowed to return. Save the Children said on Thursday that more than 2,500 foreign children living in harsh conditions in Syrian camps should be repatriated with their families to their countries of origin. The children, with nationalities from 30 countries including France, Germany, the United States and Britain, are from families with real or suspected links to ISIS. They are living in three camps in northeast Syria without proper healthcare, food or education, the charity said.