Toronto fire officials say a Christmas Day blaze that gutted two restaurants in Toronto's upscale Yorkville neighbourhood is considered "suspicious."

Toronto Fire Services made the statement in a Twitter message posted just after 1 p.m. ET Friday, one day after flames tore through Spuntini Ristorante & Bar and Sotto Sotto, leaving both smoking ruins that firefighters were still working to extinguish at mid-morning on Boxing Day.

At least 12 trucks and 45 firefighters were called to the scene on Avenue Road just south of Davenport Road at about 7:30 p.m. Thursday.

A firefighter suffered minor burns in the fire. There were no other reported injuries. Fire officials estimate the damage at $1 million.

CBC News reporter Greg Ross was at the scene Friday morning and said neighbours had gathered outside, many stunned at the extent of the damage. 

"Smoke is still billowing out of the roof of the building as the fire continues to smoulder inside. Nearly 14 hours after getting the call, firefighters are still on the scene dousing hot spots," he reported. 

Police said Friday that southbound Avenue Road will stay closed until further notice. Southbound TTC buses were also diverting around the area. 

Sotto Sotto is an upscale Italian restaurant known for catering to celebrities such as Ewan McGregor, Johnny Depp and Oprah Winfrey. Toronto musician Drake refers to the eatery in his song Pound Cake and on Friday lamented its loss online. 

"Damn. My second home. Gone but not forgotten," Drake wrote on Instagram. 

Sotto Sotto owner Marisa Rocca indicated she plans to rebuild. 

"We owe it to our history, our team and our patrons to rebuild," Rocca said in a statement. "We will come back stronger than ever." 

Damn. My second home. Gone but not forgotten. #SottoSotto

A photo posted by champagnepapi (@champagnepapi) on

At its height, the fire was visible from blocks away, as seen in the video below submitted by viewer Emma Krause.

Fire at Yorkville's Sotto Sotto, Spuntini RAW0:31