Pictures have emerged of one of the victims of an attack in which nightclub revellers were sprayed with acid.
Ex-Premier League footballer Jamie O'Hara condemned the "sick" attack as he tweeted a picture of his relative Sadie Wright's face, showing a number of burn marks.
Sharing a second picture showing damage to her scalp, O'Hara - star of Celebrity Big Brother - wrote: "Blisters all over my cousins head from acid attack… what is wrong with world that innocent people have to get hurt."
The images, which were retweeted by Ms Wright, came to light after at least 12 people suffered burns at the Mangle E8 nightclub in Dalston, east London.
Two male victims in their 20s are in a serious but stable condition in hospital.
Police believe the "noxious substance" was sprayed directly into the faces of the two men after an argument broke out in the early hours of Monday.
The suspected attacker has not been caught, police said.
A witness said they had seen a group of women pouring water on others who were apparently injured.
"In the party in the basement there were girls making noise, I saw their friends ordering a bottle of water - they were putting it on them, they were splashing it on their faces," the witness, who asked not to be named, said.
"It was like a war - the police were everywhere.
"I just saw a lot of people complaining, there were a lot of staff around, someone had called the police and a lot of people were crying."
About 600 people had been at the late-night event and about 400 were still in the building - between Sidworth Street and Warburton Road - at the time.
A London Fire Brigade spokeswoman said: "The only information that we have is that it was an unknown corrosive substance thrown within the nightclub.
"It was identified by a PH paper test as a strong acidic substance."
A journalist who was in the area at the time, Phie McKenzie, tweeted: "Scary scenes in Hackney tonight, we have heard reports of chemical burns of people in the building here".
The suspected acid attack comes just over a week after three members of a family had strong acid thrown on them in Islington, north London.
There have been no arrests so far over the assault on 8 April, which injured the father, mother and their two-year-old son.