Gas engineers are at the scene of today's huge explosion in Sunderland, trying to find what caused it.
Emergency services were called to Rosslyn Avenue in Ryhope at 8.50am, after the street was rocked by an explosion.
One semi-detached property was destroyed, and another badly damaged.
One person has been airlifted to hospital with serious burns.
A spokesman for Northern Gas Networks said: "Emergency engineers from NGN have attended the scene of an incident on Rosslyn Avenue in Ryhope, Sunderland, this morning.
“We are working alongside the emergency services, and at this stage, the cause of the incident is not yet known.
"However, we will be investigating as a matter of urgency.
“Anyone that smells gas or suspects carbon monoxide should call the National Gas Emergency Service on 0800 111 999.
"This line is in operation 24 hours per day, seven days per week.”