London, July 12 (IANS): An Australian boy, who fled his home in Sydney last year to join the Islamic State (IS) terrorist group, on Sunday threatened of attacks on Britain, media reported.

Elmir, 18, sent a message to the Daily Mail on Sunday threatening attacks on Britain. Boasting of his "connections" in the country, he warned, "brothers that I know there... are itching to do an attack".

Dubbed as "Ginger Jihadi" because of his long red hair, Elmir became a poster boy for the IS and he appeared in their many propaganda videos.

"This is a direct threat," he added.

He bragged that IS would not stop their murderous campaign until their flag flies over Buckingham Palace.

Elmir also confirmed that he married a British teenager, Amira Abase, 16 - who travelled to Syria with her two school friends from East London in February this year.

Elmir also callously mocked the massacre of 38 tourists by an IS-inspired gunman on a beach in Tunisia last month.

Police launched an investigation after the radicalised fighter sent the warning to the newspaper.