A search and rescue operation is underway at a townhouse complex in Whalan, in Sydney’s west, on Saturday afternoon.
An explosion on Waikanda Cres just before 1pm prompted the evacuation of a number of people, with more feared to still be inside the building.
“There has been a major explosion in the townhouse complex,” Fire & Rescue NSW told 7NEWS.com.au.
Know the news with the 7NEWS app: Download today 
“There is a lot of damage to the second level of the unit.”
Six people have already been evacuated from the building and assessed at the scene by paramedics, but that number could grow, NSW Ambulance confirmed.
Two of those patients have been taken to Mount Druitt Hospital, so far.
One section of building appears to have been completely flattened, in images from the scene.
Emergency services are in attendance, with 12 FRNSW appliances at the scene, and firefighters with breathing apparatuses conducting a search and rescue.
The operation is ongoing.
-More to come …