Thanks for following our live coverage today of the serious incident in the south Wales valleys and, earlier, the latest news on the coronavirus crisis.

Here are today's main developments on Covid-19:

• An extra 21,000 people in Wales have been advised to shield themselves from coronavirus because of other medical conditions they have
• Health Minister Vaughan Gething has dismissed claims that a "track and trace" policy for Covid-19 would require more than 30,000 tests a day in Wales
• Public Health Wales confirms another 26 deaths of people in Wales with coronavirus, taking its total to 1.023

We'll be back tomorrow with Wednesday's updates on coronavirus in Wales.

South Wales Police has confirmed it has launched a murder investigation after an elderly man died following an incident in the south Wales valleys.

In a statement, the force said: "Shortly after 1.45pm today police officers were called to a serious incident at a convenience store on Tylacelyn Road in Penygraig in the Rhondda.

"An elderly man has died, another man is in a stable condition at the University Hospital of Wales and two other people have suffered non life-threatening injuries.

"A 29 year-old woman from Porth has been arrested on suspicion of murder and taken to Merthyr Tydfil police station."

Image source, Wales News Service

Det Ch Insp Mark O’Shea of the force's major crime investigations team said: “This is a very tragic incident and one man has died and his family is being supported by specially trained police officers.

“Our thoughts and condolences remain with the victim’s family at this very sad time.

“This incident will have understandably caused a lot of shock in the local community and I want to reassure residents that a full investigation has been launched.

"However, we are not looking for anyone else in connection with this incident.”

South Wales Police is appealing to any witnesses who have not yet come forward to contact them on 101 or Crimestoppers anonymously on 0800 555111 quoting reference 2000153856.

The force also said it was referring the matter to the Independent Office of Police Conduct.

"I'm shocked, and I'm sure most people in our small and close-knit community here in Penygraig will be shocked as well," said Rhondda's Welsh Assembly member Leanne Wood, who lives near the scene.

"It's my local grocery store, it's where my family get most of our day-to-day goods," told BBC Radio Wales.

"We know the staff there, we know a lot of the shoppers who will be using not just the Co-op but the whole of the Penygraig main road.

"It's not something any of us expect to happen in our community. It's something you see in the news happening in another place, but you don't expect it to happen on your own doorstep."

Ms Wood, a former leader of Plaid Cymru, also praised the emergency services.

"The police and ambulance workers are already under incredible strain with the Covid-19 outbreak, and to have something like this on top is awful really," she said.

There'll be live updates from the scene of the incident in Penygraig on BBC Wales Today, starting at 18:30 BST on BBC One Wales.

One person is believed to have died and several others have been injured following what an eyewitness said was a "stabbing" incident in the south Wales valleys.

Eyewitnesses described seeing people running from the Co-op store in Penygraig this afternoon.

South Wales Police said one woman had been arrested after a "serious incident at the location", with the public advised to avoid the area.

A man who answered the telephone at the Co-op store said: "Really sorry, not answering anything." Businesses in the village have been told to lock their doors, as police and ambulances arrived."

Rhondda MP Chris Bryant says the incident will "just be utterly shocking" to people in his constituency.

"This isn’t what you expect to happen in the Co-op in Penygraig,” Mr Bryant told BBC Radio Wales.

“In fact, members of my staff often pop up there for a sandwich at lunchtime.

“Everyone will be quite shocked," the Labour MP continued.

"We don’t know the circumstances at all, police are trying to track down all the elements of it at the moment.

“Against the background of the coronavirus it all feels even odder.

“You couldn’t get more ordinary or normal than the Co-op in Penygraig could you?

“It is slap bang in the middle of the community and everyone knows where it is, so everyone will be saying to themselves ‘my God that could have been me.’

“I am trying to liaise with the police and emergency services to ensure we support the individuals and families hit and hurt by what has happened.”

Image source, House of Commons

A woman has been arrested and four people have been taken to hospital following a "stabbing" in the south Wales valleys.

Police were called to Tylacelyn Road, Penygraig, at about 13:50 BST and the Welsh Ambulance Service said it treated those who were injured.

An eyewitness said her husband was told there was a woman inside the Co-op "stabbing people".

People have been told to stay away from the scene, while local politicians have said their thoughts are with those affected.

Image source, Wales News Service

Forensics teams are still at the scene of the incident, to which emergency services were alerted shortly before 14:00 BST.

Image source, Wales News Service

Image source, Wales News Service

Leanne Wood, the local Welsh Assembly member for Rhondda, has posted a video offering her "heartfelt sympathies" to everybody affected.

The Plaid Cymru AM said staff at the shop "must have been traumatised to witness such horror".

In a statement, the Welsh Ambulance Service said four people were taken to hospital, but gave no details of their condition.

It read: “We were called today, Tuesday 05 May 2020, at approximately 1.50pm to reports of an incident on Tylacelyn Road in Tonypandy.

"We sent one rapid response vehicle, three emergency ambulances, two advanced paramedic practitioners and our Hazardous Area Response Team, who were supported by an air ambulance.

"Four people were taken by road to Cardiff’s University Hospital of Wales and the Royal Glamorgan Hospital.”

Joshua Davies, a local councillor for Penygraig, said: "It's a horrific time, and a sad time."

He told the Gareth Lewis programme on BBC Radio Wales: "Our thoughts are with the family and friends of everybody who has been involved in the cases today.

"We have no information currently as it stands, but as soon as we do have any information, we will share it with you as soon as we can."

On the "significant" response from the emergency services to the incident, Mr Davies added: "There has been an absolute significant response from the police and every emergency service that has turned up today.

"I put on record my thanks to the emergency services for their fast response today, to the incident that has taken place."

A witness told the PA news agency: "I just saw a hat and cans on the floor outside the Co-op as I was pulling up and thought 'that's strange', then paramedics arrived.

"My husband went to go into the Co-op but got stopped by people who told him that there was a woman inside with a knife who was stabbing people.

"I stayed in the Jeep and more police and paramedics arrived and they went to a man who was in the van parked in front of my Jeep.

"This was the man who had been stabbed repeatedly, they took him out of the van and placed him into the ambulance."

BBC Radio Wales

BBC reporter Stephen Fairclough has been updating BBC Radio Wales listeners from the scene.

“We know the incident began this afternoon, it was early afternoon.

"It centred on the Co-op supermarket, which is just behind me here in Penycraig.

"It’s the largest food shop in the town. It’s understood there were multiple casualties.

“The area around the Co-op, the main street in Penygraig and many other streets in the area have been sealed off by police.

“Witnesses have told me that the police arrived very quickly and that there were a lot of them.

“We know one woman has been arrested. There are forensic officers here in their white suits examining the scene.

"They and other emergency services and investigators will continue to be here quite clearly for some time to come.”

Rhondda Cynon Taf council is working with the police to provide reassurance to the community.

Leader Andrew Morgan said: “I have this afternoon been made aware by the police of the serious incident which has occurred in Penygraig today.

“My thoughts are with the families and friends of those involved in this awful incident.

“More details will be issued by the police in due course, but council services stand ready, working alongside South Wales Police, to provide reassurance and support to the community at this very difficult time.”

Image source, Wales News Service

There is a large presence of police and forensic officers at the scene in Penygraig.

Image source, Wales News Service

Image source, Wales News Service

Image source, Wales News Service

Eyewitness Ravi Raj, who runs the nearby Post Office, said: “I was in the Post Office and I heard people running so I popped out to see what was happening.

“Then the police vehicles came. I’ve never seen that many.

“I saw one man bleeding heavily from the back of the neck. Paramedics were helping him.

"A woman was injured too, bleeding from her neck.

"I’ve never seen anything like this before here.”

A takeaway owner in Penygraig said a woman came into his shop bleeding following the incident.

He said he was not present at the time, adding: "She told my nephew, 'Put the shutters down, put the shutters down'.

"She was bleeding and he called the police and ambulance straight away."

The leader of Rhondda Cynon Taf council Andrew Morgan says he has spoken to police about the incident in Penygraig.

"My thoughts are with everyone involved," he says.

Jason Locke shared a video of Wales Air Ambulance landing near the scene of the incident.

The incident happened in Penygraig, which is a village near Tonypandy in the Rhondda valley in south Wales.