Police hunting for attackers who threw acid over two British teenagers say they will do "everything they can" to catch the perpetrators.
The statement from police comes as a radical Muslim preacher wanted in connection with the attack on Kirstie Trup and Katie Gee in Zanzibar has gone on the run after being shot by officers.
Sheikh Issa Ponda Issa was hit in the shoulder with a tear-gas canister as he tried to escape from officers after being cornered near Tanzania's capital Dar es Salaam.
Locals look at newspaper headlines in Stone Town, where two young British women suffered an acid attack, on the Indian Ocean island of Zanzibar
Faustine Shilogile, a police commander in Morogoro, where the sheikh was shot, said: "He has not been arrested. He has been shot at. We have been looking for him in all corners of the country."
The victims, both 18 and from north London, continue to be treated in Chelsea and Westminster Hospital, where they are said to be "well rested and comfortable".
The police commander said: "We are no closer to finding who was responsible for this. But this is a serious police investigation, and we are doing everything we can."
The women are spending a third day in hospital after being admitted on Friday. They are receiving treatment for burns inflicted in an unprovoked attack while they were on a volunteering holiday on the island, off the coast of Tanzania.
Members of both teenagers' families are keeping a bedside vigil, after the pair were flown home and immediately sent to the capital's regional burns centre.
The burns sustained by one of the girls
A hospital spokesman said today: "The patients are well-rested and comfortable at the hospital. They have been with their families all day.
"Doctors are continuing to assess treatment options for both patients."
Meanwhile, Tory MP Bill Cash, who sits on the All-Party Parliamentary Group for Tanzania, has urged the Foreign Office to further upgrade its travel warning for tourists visiting both Zanzibar and Tanzania because the attack was "more than just an ordinary criminal event".
The Foreign Office updated its Tanzania travel advice page on Friday with details of the attack and is warning British nationals to "take care" and read the guidance.
Mr Cash told the Sunday Express: "People need to be extra-vigilant and the Foreign Office and High Commission need to make a very thorough evaluation of the threat, as these latest attacks would seem to be on religious grounds.
"The threat to tourists going to Tanzania and Zanzibar needs to be upgraded, without doubt."
Miss Gee has already taken to Twitter to say: "Thank you for all your support x".
A photograph released by the teenagers' families showed the injuries one of them suffered in the attack.
She is shown wearing an open striped shirt and a silver necklace and what appear to be acid burns are clearly visible on her chin, neck and upper chest.
One of the victim's injuries are much worse than her friend's, it was reported, because helpers used dirty water on her burns.
Her friend was reportedly immersed in the sea in the aftermath of the attack at Stone Town, a beach resort, and the salt water helped her skin.
"That completely altered the result: the salt water and the acid," Miss Trup's father, Marc, said. "The other girl panicked, ran around, made her way to a public toilet."
When "they got to the medical centre there was no shower", he added. "They were throwing dirty water at her."
British tourist Sam Jones told how he desperately tried to help one of the women as the acid burned through her skin following the attack on Wednesday night.
Mr Jones, who was on holiday on the island with his girlfriend Nadine, told The Sun how he heard their screams following the attack and found one of them crouching by a toilet block in pain.
"She just kept screaming that she needed water," he told the newspaper. "My girlfriend grabbed a hose and we started to wash her down as best we could."
The couple said they supported the injured women by joining them on a private plane to Dar es Salaam for treatment.
Police said five men are being questioned by officers on the Indian Ocean island after the women were attacked by men on a motorbike as they walked along a road.
Zanzibar's assistant police commissioner Mkadam Khamis Mkadam told an east African newspaper: "They were accosted by two men riding a motorcycle ... they poured this liquid ... we suspect it [was] an acid, before they ran away."
The young women were enjoying the last week of a trip as volunteer teachers to the predominantly Muslim island when the corrosive substance was thrown at them in an apparently unprovoked attack.
They had originally planned to return in time to collect their A-level results next week, with Miss Trup hoping to study history at the University of Bristol while Miss Gee is considering the University of Leeds, it was reported.