According to witnesses, several police cars are parked in the village, with the air ambulance landing nearby. One said there was possibly 20 to 30 emergency vehicles at the scene. A smaller cordon has been set up within the larger cordon on Baglan Street.
Another witness told WalesOnline: “I can count six ambulances, eight police cars and four first responders.”
Rhondda MP Chris Bryant said: “I have been informed that the incident in Ynyswen is a major incident.
“The emergency services will be in attendance for a very long period of time.
“Please do avoid the area.
“I sincerely hope nobody is extremely hurt.”
He also thanked the emergency services who are in attendance.
Mr Byrant tweeted: “I’m aware of disturbing events on Baglan Street in Treherbert/Ynyswen.
South Wales Police confirmed they were dealing with a “serious incident” which involves a “number of casualties”.
A spokesman said: “Police units are currently dealing with a serious incident which occurred in Baglan Street, Treorchy, at around midday today.
“Ambulance crews are also in attendance as the incident involves a number of casualties.
“The street has been closed off and people are advised to avoid the area until further notice.”
One person at the scene said they had never seen a police presence like it before.
They said: “I’ve never seen a police presence like this before.
“It’s clearly a major incident.”
It is believed officers are carrying out investigations along Baglan Street.
Another witness claimed their saw police officers with guns before saying they saw someone being “stretchered” into an ambulance.
They said: “I live in the street, it was about half-past 12 on my way to meet my friend.
“As I came around the corner there were loads of sirens getting passed and I saw four police at the bottom with guns telling people they couldn’t come down the hill.
“They were saying can you get back.
“Then a couple of minutes later I saw someone getting stretchered off into the back of an ambulance literally outside the Chinese by the hill.”
A spokesperson for the Welsh Ambulance Trust confirmed they were called to the scene at around noon today.
However, they did not say how many people were taken to the hospital.
They confirmed to WalesOnline one rapid response vehicle, three emergency ambulances and the air ambulance were sent to the scene.
More to follow…