The hunt for the thugs who deliberately hurled acid in the face of a three-year-old boy in Worcester reached London today as three men were arrested 130 miles away in the capital overnight.

The mother screamed 'what have they done to my baby?' as the child was doused in a corrosive liquid in what police believe was a targeted attack in Britain's safest city on Saturday.

The toddler suffered serious burns as he sat in his pushchair in a Home Bargains shop on the city's Shrub Hill Retail Park.

The acid was thrown over him while he was out with his family and a witness said the little boy's mother was holding her head in her hands as she wept outside the shop.

Following the arrests of three men aged 22, 25 and 26 in London this morning and another of a 39-year-old man in Wolverhampton yesterday, police have now held four people all on suspicion of conspiracy to commit grievous bodily harm.

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West Mercia Police believe the child was deliberately targeted in Home Bargains on Shrub Hill Retail Park at Tallow Hill. They have released images of three men (pictured) they would like to speak to

Police have now arrested four men - but none of them in Worcester. Three were in Walthamstow, London, last night and another in Wolverhampton

The shocking moment a three-year-old boy had acid deliberately hurled in his face was captured on CCTV, police have confirmed.

Chief Superintendent Mark Travis said: 'The incident was captured on CCTV but we will not release any footage that showed the substance being thrown or sprayed towards the little boy.

'A number of other exhibits from the area have also been taken for examination in the next couple of weeks.

'We have looked at the movement of people in the footage throughout the area and consider this to be a deliberate act against the little boy.

'The substance that was used is an acid or an alkali substance with caused the boy a degree of discomfort, we are finding out the nature of the substance as part of the investigation.'

West Mercia Police said the family of the little boy were coming to terms with the 'shocking' attack.

Speaking at a press conference at police HQ in Worcester, Chief Superintendent Travis said: 'There is nothing to suggest that this is incident is in anyway motivated by race or anything to do with the EDL protest that took place in Worcester this weekend.

'I think it's a natural question people would ask but we're really, really confident that they're not connected.'

Chf Supt Travis hinted that the motive behind the acid attack may have been as a result of a 'dispute between communities'.

He added: 'The family are coming to terms with something that is quite shocking.

'It's a difficult time for them and we need to make sure that while we work through the investigation they are safe and secure and are allowed to deal with the issues that they face.

'As a local policing commander in support of our local community I want to make sure the message is really clear that this is a very, very rare occurrence and what we will do is work to make people understand that this is not the way to resolve issues and disputes in communities.

Chief Superintendent Mark Travis said: 'At this time we are treating this as a deliberate attack on a three-year-old boy.' Pictured: The men wish to speak to

The child was treated in hospital for burns to his face and arms before being released yesterday afternoon. However, the long-term effects of his injuries are unknown.

Police yesterday issued a public appeal, releasing CCTV images of three men who were seen around the child at the time of the incident.

Shocked residents of the cathedral city, known for its low crime rate, last night condemned the attack as 'absolutely pure evil'.

Witnesses described the anguish of the mother, saying: 'There was a bit of shouting and screaming in the store but then it all went quiet.

'But then this woman ran outside and started screaming that her baby had been hurt and needed help.

'The mother was sitting outside the shop, screaming: 'My baby, my baby, what have they done to my baby?'

'She was in floods of tears and people from the shop were telling her they had called an ambulance and her child would be well looked after.'

The attack happened in a Home Bargains store in a retail park in the Tallow Hill area of the city on Saturday afternoon.

Shopper Rachel Bryant told The Daily Star: 'When I heard about the acid attack I couldn't believe it.

'It's horrendous to think something like this could happen to a little boy in the middle of a shop.'

Although detectives have not ruled out a racial motivation, they have said it is not thought to be linked to a march involving the far-Right English Defence League which took place in Worcester on the same day.

Mayor of Worcester Jabba Riaz also said there was no link between the two incidents.

The investigation has moved rapidly, with a 39-year-old man from Wolverhampton arrested on suspicion of conspiracy to commit grievous bodily harm. He remains in police custody.

Chief Superintendent Mark Travis added: 'Officers are working hard to establish exactly what happened and what the substance involved was.' Pictured: The store in Worcester

Police officers conducting a search of Shrub Hill Retail Park in Worcester on Sunday

Police have also issued an appeal showing three men captured in a CCTV image. In it, they are wearing casual clothing and sunglasses, and can be seen leaving the store and heading towards the city centre.

Last night it was claimed that one of the men pictured was seen in a pub car park smoking cannabis shortly before the attack.

Chief Superintendent Mark Travis of West Mercia Police said the boy, believed to be from Worcester, is now recovering at home with his family.

However, he stressed that the long-term implications of the child's injuries are unknown.

The very thin blue line: he's made of paper Pictured: The cardboard PC The police officer looked a bit wooden, and as shoppers got closer, they could see why. This life-size cardboard policeman was spotted in the Worcester branch of Home Bargains yesterday. Flat-pack PCs are an increasingly popular way for cash-strapped forces to boost their street presence. They are often seen in petrol stations to deter motorists from driving away without paying and in shops to discourage shoplifting. Advertisement

He said: 'Clearly we are working with the family to understand the motive of the attack.

'The child was with family members and was being well looked after and remained with family all the way through to hospital.'

He added: 'At this time we are treating this as a deliberate attack on a three- year-old boy.

'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.'

Chief Superintendent Kevin Purcell renewed the appeal, tweeting: 'Really nasty crime this.

'These men are very distinctive. They clearly from behaviour know each other well. If you know them please let us know.'

One shopper added: '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.'

Officers are investigating a suspected acid attack on a three-year-old child on Saturday

Worcester City Council leader Marc Bayliss described the attack as 'absolutely pure evil'.

He added: 'I have never heard of an acid attack in Worcester so this is absolutely not something we have any experience of.

'If anything knows anything about this I would urge them to come forward.

'Think if this was a member of your family, an innocent child.'

Robin Walker, the MP for Worcester, described the incident as 'horrific', adding: 'The shock will be universal, anyone conducting such an attack on a small child is just appalling.

'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.'

A Home Bargains spokesman said: 'Our thoughts are with this young child and his family at this very difficult time.'

Worcester is known for its low crime rates and in 2016, was named the safest city in England.