Allegations that patients died after ambulance delays are to be the focus of a high-level "risk summit", a health minister has announced.
Conservative Steve Barclay told the Commons that claims against the East of England Ambulance Service Trust had been raised with senior NHS officials.
He said NHS England and NHS Improvement are meeting with the Care Quality Commission to discuss concerns.
Last week Clive Lewis MP said 20 people had died after ambulances arrived late.
The Labour MP for Norwich South said the incidents, revealed by a whistleblower, took place over a 12-day period where the ambulance service had failed to move into its highest state of emergency.
Speaking during a Commons debate, former Liberal Democrat health minister Norman Lamb encouraged Mr Barclay to reiterate that ambulance trust managers should allow staff to speak out when they have "genuine and legitimate" concerns.
Mr Barclay gave his support to this and and later referred to the East of England Ambulance Service Trust, adding to Mr Lamb: "On receipt of his letter I instructed officials in my department to share copies with the Care Quality Commission... to ensure they're fully aware of the issues being raised.
"I've discussed these concerning allegations directly with the chief executive of NHS England and the chief executive of NHS Improvement this morning.
"They have subsequently confirmed they will be holding a joint risk summit regarding the trust in the next week - the Care Quality Commission will be in attendance."