Authorities are expecting the worst as 68 wildfires continue to burn in Australia - 22 of them out of control - and dangerous weather conditions forecast through Thursday.
"There will be a significant impact on populated areas should all these forecasts materialise as is being suggested," Shane Fitzsimmons, New South Wales Rural Fire Service Commissioner, told reporters.
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Scotland Yard said the male youths will appear in custody at Westminster Magistrates' Court on Saturday.
Windy this weekend with gales across northwestern parts of the UK. Rain spreading southeast.
Greater Manchester Police said "inquiries are ongoing to fully understand the circumstances of the incident."