A 17-year-old Irish boy caught up in violence in Cairo and detained by the Egyptian authorities might have been "beaten to hell", his sister has claimed.
Ibrihim Halawa, 17, and his three sisters Omaima, 20, Fatima, 22, and Somaia, 27, were among hundreds of people cleared out of the Al Fateh mosque when security forces stormed the building on Saturday.
Their sister Nasaybi Halawa, at the family home in Dublin, said she believed her siblings are being held at Tora prison, where all the men have been beaten.
"I was speaking to someone a few minutes ago and they told me that they saw my sister in Tora jail and I asked them about my brother," Ms Halawa said.
"The person I'm speaking to told me they were beating men to hell. She doesn't know how my brother looks but she told me 'I can guarantee for you, all the men were beaten there. They didn't exclude anyone from hitting them'."
Ibrahim, who completed his Leaving Certificate before the summer, was due to receive his college and university offers from CAO today.
Instead, his family are left at their home in Firhouse, south Dublin, fearing for his and his siblings' safety.
Ms Halawa said she believes the Egyptian authorities were trying to "plan a charge" for their detainees.
The siblings' father, Sheikh Hussein Halawa - the imam of Ireland's largest mosque - has appealed for the Irish Government to act quickly.
It is understood that an Irish representative will attend a prosecutors' office in Cairo today to discuss the ongoing detention.
Ms Halawa said she was worried her siblings would be killed.
"There is no difference now between anyone. They can kill anyone," she told RTE Radio.
"We don't know anything about my brother and sisters. We don't know if they are safe.
"We don't know if they are eating or drinking, where they sleep now, whether they have had any food since they left the home last time. We don't know anything about them."
Senior European diplomats are preparing to meet in Brussels today to discuss the crisis in Egypt.
The Muslim Brotherhood has claimed that dozens of detainees were killed overnight.
It is understood that some may have suffocated in the back of a truck as they were being transported to a prison.
Tear gas was fired and heavy gunfire was heard before the mosque, in the Ramses area of Cairo, was cleared on Saturday.
The Halawa siblings have made no direct contact with their family since. It is understood their mobile phones were seized.
It is also understood that the siblings' mother, who is staying with relatives in Egypt, had been contacted by a woman who had seen Omaima in one of the detention centres.
The Irish Department of Foreign Affairs has said it continues to work closely with counterparts in Egypt in a bid to secure the safe release of the family.
The Halawas had travelled to Egypt earlier this summer for a holiday and were joined by their mother a fortnight ago.
They were forced to seek sanctuary in the Al Fateh mosque on Friday after violent clashes between supporters of ousted president Mohammed Morsi and the security forces killed around 80 people. More than 800 people have died in the carnage that has followed a military crackdown over the past five days.
He said a Turkish diplomat talked to the family in Tora prison yesterday, who confirmed they were all safe and had been kept together.
The siblings will be taken to a prosecutors' office in Cairo at 2pm today, with a representative from the Irish Embassy in Egypt.
"We will find out today what the attitudes of the authorities are towards the Halawas and we will be able to inform their father and sister back in Ireland," Mr Costello said.
"It's good news that the Turkish diplomat spoke to them as late as yesterday and it's a relief to hear that they are in good form and that they have been kept together.
"That was a big concern, that they may have been separated. But we'll find out the attitude of the authorities today and we'll move from there."