Louise Parry
BBC News, Essex
Aaron Chesham
Two air ambulances attended the incident and five children were taken to hospital by land ambulance
Two children have been taken to hospital with serious injuries after a tree fell in a seaside park.
Essex Police said there were "a number of casualties" after the "serious incident" at Chalkwell Park in Southend-on-Sea.
The force was called shortly before 15:00 BST on Saturday and was at the scene along with ambulance and fire service teams.
"We would please ask the public to avoid this area where possible while this work continues," police said in a statement on social media.
An East of England Ambulance Service spokesperson said: "Two children were transported by road to Southend University Hospital.
"A further three children were later transported by road to the same hospital with minor injuries."
They added that "six ambulances, three ambulance officer vehicles, the London Air Ambulance and Kent Air Ambulance were sent to the scene".
Aaron Chesham
Emergency services were called just before 15:00 after a tree fell in Chalkwell Park in Southend
The MP for Southend West and Leigh, David Burton-Sampson, told the BBC:
"I am aware of the terrible accident that has happened at Chalkwell Park this afternoon involving a fallen tree.
"My deepest thoughts are with all those who have been impacted
"I encourage people not to speculate at this stage but to avoid the area and allow the emergency services to do their work."