A three-year-old boy in a pushchair suffered serious burns to his face and arm after being hit with acid in a Worcester shop, police have said.
West Mercia Police believe the child was deliberately targeted in Home Bargains on Shrub Hill Retail Park at Tallow Hill yesterday afternoon.
They have released images of three men they would like to speak to.
The boy was taken to hospital, where he was treated for burns, but has now been released. He had been shopping with his mother when a substance was thrown or sprayed at him, police said.
A 39-year-old man from Wolverhampton has been arrested on suspicion of conspiracy to commit grievous bodily harm and remains in police custody, the MailOnline reported.
Chief Superintendent Mark Travis said: "A young family were out shopping and a substance appears to either have been thrown or sprayed towards a three-year-old child who was in a pushchair."
He added: "He has burns to his face and to one of his arms - at the moment we are uncertain about the long term implications of those burns but we do hope that these won't be life-changing injuries."
He renewed the appeal for information about the three men in the images, who left the store in the direction of the city centre, and also for anyone who has seen "anything discarded in the area".
At a press conference at the Worcester store, he added: "A family was shopping and a young child of three was in a pushchair and it would appear that some form of substance - either an acid or alkaline - has been thrown or sprayed towards that child.
"As a consequence of that, the child has has received some form of burns. The staff and emergency services supported the family at the scene and the child was then taken to a local hospital, where they were treated for burns.
"The child received injuries to his face and arms. I am really pleased to say that subsequently today that child has been released from hospital and is back with family and we have specialist officers supporting the family.
"The child was with family members and was being well looked after and remained with family all the way through to hospital.
"At the moment we are really trying to understand the motive - so consequently the three men in the images we released, we would really like to speak to them.
"They were seen near the child at around the time of the incident and left the store shortly afterwards - we believe they may have information that may help us to understand what took place.
"At the moment we don't have any knowledge of any particular vehicle that might have been involved in the incident - we would really happy to hear from any member of the public who think they may have information."
Earlier, Ch Supt Travis said: "At this time we are treating this as a deliberate attack on a three-year-old boy.
"The incident will rightly shock the local community and I would like to reassure local people that we are carrying out a thorough investigation to identify those responsible.
"At this time, the motive for the attack is unclear.
"Officers are working hard to establish exactly what happened and what the substance involved was.
"The three men in the photo may have information vital to our investigation.
"I am sure someone will recognise them and I would urge anyone with information to contact us as a matter of urgency."
A spokesman for the West Midlands Ambulance Service said it was called to Home Bargains at 2.24pm on Saturday "to reports of a young boy who had suffered a severe reaction to an unknown substance".
"An ambulance was sent and arrived in eight minutes. The crew assessed the boy at the scene and liaised with the trust's hazardous area response team for specialist advice.
"After treatment, he was taken to hospital in Worcester."
Shocked shoppers have described seeing police cars and ambulances dashing to the shop where the three-year-old boy was attacked by a 'skinny white guy'.
Rachel Bryant, 22, said: "I'd been shopping with my mum and were heading to Home Bargains when there were loads of police and ambulances.
"I saw a woman crying and being comforted by police. I didn't know what it was all about. When I heard about the little boy being attacked with acid I couldn't believe it. I assume the woman I saw could have been his mum or relative.
"It's horrendous to think something like this could happen to a little boy in the middle of a shop on a Saturday afternoon."
Another shopper, who did not want to be named, said: "I heard from someone who works at the shop that the man [who attacked the boy] was a skinny white guy.
"He was about 5ft 11ins and he ran out the shop. I think he was caught pretty quick but I don't know for sure.
"Some people have said it could be connected with the EDL march in town about the same time but, again, it's all rumours at the moment."
Home Bargains shopper Barry Keville, 64, said: 'It's diabolical. You hear about it in other towns and cities, we think that's not close to home but when it's this close to home it's quite frightening as you use the shop.
"You wonder what is going to happen next."
Dean Carey, 22, assistant manager at the store, said: 'Events happened yesterday, police knew what happened and we are working with them.
"Everything is fine, everything is nice and safe for everyone, the staff are all fine. The incident happened but now we have moved one."
The store's area manager, who did not want to be named, added: "We put the health and safety of our staff and customers at the forefront before anything else.
"Police are still investigating and as far as we are concerned Home Bargains are assisting the police investigations."
The shop reopened at about 11.40 this morning.
Worcester City Council leader Marc Bayliss said the attack was 'absolutely pure evil' and added: "Worcester is not that sort of place. We are a quintessential small English city.
"I have never heard of an acid attack in Worcester so this is absolutely not something we have any experience of. We are a very safe city, we are one of the safest places in England according to statistics.
"If anybody knows anything about this I would urge them to come forward - think if this was a member of your family, an innocent child, a three-year-old probably scarred or damaged for life by this.
"We need to bring the perpetrators to justice, and quickly."
The deputy leader of Worcester City Council, Adrian Gregson, said he was in the shop next to Home Bargains shortly after the attack.
He added: "I was in the shop next door when it was going on, it was around mid-afternoon.
"I didn't know what the situation was - there were a couple of fire engines and a fire incident vehicle and a police car. By that point the ambulance had been and gone.
"It is the first time, as far as I'm aware, this has happened in Worcester."
Robin Walker, MP for Worcester, described the incident as 'horrific' and urged anyone with information to contact the police.
"The shock will be universal, anyone conducting such an attack on a small child is just appalling," he added.
"It's an issue which rightly there has been a lot of concern in Parliament and a move to toughen sentences for any kind of acid attack.
"But particularly the nature of this being a small child is very concerning indeed.
"At this stage the key thing is for the police to act quickly and see if they can track down the perpetrator and understand what's behind it because it is an unthinkable thing to happen."
Police Crime Commissioner John Chapman said: "This sort of crime is exceptionally rare in West Mercia, but such an attack has no place in any community whatsoever, particularly when a young child has been hurt.
"It is understandably upsetting for people in Worcester and further afield.
"I would ask our communities to unite together and support the police by sharing appeals or passing on any relevant information.
"I am receiving continual updates from the police force. I am confident they have all the skills and resources needed to progress this investigation and bring any offenders to justice."
A Home Bargains spokeswoman said: "Our thoughts are with this young child and his family at this very difficult time."