Updated at 10:50 p.m. ET
Prime Minister Scott Morrison is calling up 3,000 reservists for operations related to the massive bushfires in eastern Australia that have forced mass evacuations and killed at least 11 people since Monday.
Record heat has contributed to the ferocity of blazes. Flames now threaten the outskirts of the country's largest city, Sydney.
Authorities are warning of worsening conditions over the weekend. The rural fire service deputy commissioner for New South Wales, Rob Rogers, has warned of the "frighteningly quick" advance of the blazes.
"With the fuel loads that we've got and the drought conditions and the current weather conditions that we have, frankly, we can't put these large fires out," Mick Holton, president of the Volunteer Fire Fighters Association, told NPR's Morning Edition.
Holton says firefighters are at the mercy of changing weather conditions.
"We're paying the price for probably lack of fuel management," he added.
Forecasters from Australia's Bureau of Meteorology expect the weather on Saturday to intensify the fire dangers in New South Wales and Victoria.
In a Saturday morning local time update, one forecaster said, "The changes arriving later in the day today, in comparison to New Year's Eve, [are] giving more time for those strong" winds to affect the fire regions.
Temperatures are expected to reach into the low- to mid-40 degrees Celsius in some parts of the two states. That's between 104 and 114 degrees Fahrenheit.
The warnings come after two people were killed Saturday in a blaze that devastated a large swath of Kangaroo Island, police told the Australian Broadcasting Corporation.
ABC reports "up to 150,000 hectares — about a quarter of the island — has been burnt and authorities are warning of significant property losses."
"Victoria Police Chief Commissioner Graham Ashton said the number of people missing now stood at 21, seven fewer than the number unaccounted for 24 hours earlier," ABC reported.