LOS ANGELES, Dec. 25 (Xinhua) -- Even on Christmas Day, more than 1,500 firefighters are still battling the Thomas Fire, the largest wildfire on record in history of the U.S. western state of California, said the California Department of Forestry and Fire Protection (CAL FIRE) on Monday.

The Thomas Fire continues to burn but 86 percent of the fire was contained as of Monday morning. Over the past 21 days, the fire has scorched 281,620 acres (1,139.6 square km). A total of 1,063 structures were destroyed and 280 structures damaged to date by the blaze, CAL FIRE said.

Some 1,586 firefighters could not spend Christmas Day with their families, remaining on the line.

"Firefighters are building upon previous gains by strengthening established containment lines adjacent to communities and other infrastructure. Mop up operations along the fire perimeter and active patrol are ongoing," CAL FIRE said in a statement. "Firefighting crews and aircraft remain available in the event there are flare-ups or new fire starts in the area."

California has endured an unprecedented fire season thus far. Dynamic wildfires caused extensive damage to residences and infrastructure and continue to pose a direct threat to public health and safety. There have been over 8,747 fire in total in the state this year.