The fires have destroyed at least 200 homes in New South Wales as of Saturday, the Australian Broadcasting Corp. reported.
A 63-year-old man died of a suspected heart attack Friday while he was working with neighbors to save his heritage-listed homestead.
Rural Fire Service Commissioner Shane Fitzsimmons said firefighters are facing "very bad and difficult fire-danger ratings."
"We have a lot of fire and given the indicative forecast for weather deteriorating -- and deteriorating potentially quite significantly towards the middle of the week -- we have got the likes of Blue Mountains facing one of its biggest fire risks for decades," Fitzsimmons said. "We are really concerned about the next few days and particularly towards the middle and end of next week, particularly in relation to the weather forecast."
Investigators said Saturday that they believe at least two of the fires -- the Springwood and Mt. Victoria -- were sparked by power lines that were damaged by strong winds, CNN reported.
The Australian military is looking into whether a training exercise using explosives may have caused some of the other fires burning near Lithgow, the BBC reported.
The exercises took place at a military base on Wednesday.
"The fire started on 16 October, the same day that defense personnel were conducting an explosive ordnance training activity," said a statement from the Australian Defense Force. "Defense is investigating if the two events are linked. Our thoughts are with those who have lost property or whose property is threatened by these devastating fires."
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