The East of England Ambulance Service is urging people to only call for life-threatening illnesses and injuries as they are under "extreme pressure".
The warning comes as ambulances have been delayed outside hospitals after a high number of calls.
As a result, the ambulance service has "increased" their escalation state across its service and members of the public have been asked to only call in serious situations.
A spokesman for the ambulance service said: "Our service is under extreme pressure with many ambulances delayed outside hospitals and high call volumes.
"To help us respond effectively we have increased our escalation state across the Trust.
"We urge the public to please support us by using our services wisely and only calling for life-threatening illnesses and injuries."
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