Unable to hide her anguish, Nicky Gee fought back tears as she watched daughter Katie and her friend Kirstie Trup leave the back of an ambulance wrapped in protective blankets.
The pair, both 18, arrived back in Britain after being medevaced to RAF Northolt.
They were then taken to the Chelsea and Westminster Hospital for urgent treatment to wounds, described as 'absolutely horrendous' and 'beyond imagination' by Katie's father.
He said: ‘The photographs I have seen are absolutely horrendous.
'The level of the burns are beyond imagination.'
Both British teenagers suffered horrifying burns when acid was thrown in their faces as they walked to a restaurant on the Muslim holiday island of Zanzibar.
It was the third attack on them during their stay on the island.
Police have revealed that seven suspects - including a tour guide - were detained on Thursday and in the early hours of this morning in the capital Stone Town, where Kirstie Trup and Katie Gee were attacked, a senior officer told The Telegraph.
And a £4,000 reward is now being offered by Zanzibar police for information leading to the capture of attackers, according to the BBC.
Friends suggested they could have been targeted because they are Jewish, and local police said they wanted to speak to a radical Islamic preacher who could have inspired the attack.
Police have also issued a warrant for the arrest of Islamist preacher Sheikh Issa Ponda Issa, amid suggestions his teaching could have inspired the acid attacks.
Five of the seven people, which also included market traders, have now been released while two remain at Zanzibar Police headquarters.
Regional police commissioner, Mkadam Khamis, said: 'We have interrogated seven people, including a tour guide, and traders who where close to scene.
'Unfortunately many are not providing clear information about the incident to lead us to specific conclusions yet. We need more time to continue with the investigation and more of our investigators are out in the field.'
The attackers have been described as two youths on a motorbike.
Commissioner of police Mussa Ali Mussa said few locals had witnessed the event, which took place in a narrow street as the teenagers made their way to an Ethiopian restaurant.
He said: 'There were at least six people, all foreigners, walking in pairs but distanced from each other. The young British women were also walking in a pair. It is still difficult to find eyewitnesses since the group around them were tourists.'
The girls are currently receiving treatment at the Chelsea and Westminster Hospital after they were flown back to the UK.
In a statement outside the hospital this evening, Mr Andy Williams, consultant burns and plastic surgeon, said: 'We can confirm that Katie and Kirstie have been transferred to our care at Chelsea and Westminster Hospital's burns unit where we're still assessing their injuries.
'Both girls are well and their families are with them. They will be staying at Chelsea and Westminster Hospital.
'Both families would like to thank everyone that's helped to bring the girls back.
'The families now wish to have time with the girls and that the media would respect their privacy at this difficult time.'
Arriving in a black Audi at the air base this morning Katie's concerned mum Nicky opened spoke of the the families' ordeal.
'We spoke this morning and she said she was ok. I don't know what's going on at all.
'I can't say anymore because we have to get in to see them both.'
Two crews from St John's Ambulance arrived at the Middlesex military base, which also handles private flights, at around 10am this morning.
A paramedic, who wouldn't give his name, confirmed the crews had come to pick up the teens.
He said: 'We are here to pick up the two girls.'
He refused to say if they were going home or straight to hospital.
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