A 14-year-old British boy has been arrested in connection with an alleged Islamic State-linked plot to attack a World War One commemorative event in Australia this week, police said on Monday.
Australian Prime Minister Tony Abbott said five teenagers had been detained in Melbourne on Saturday, over an alleged plan to attack an event to mark the centenary of the landings at Gallipoli.
The British teenager was also arrested on Saturday, on suspicion of being concerned in the commission, preparation or instigation of acts of terrorism after communication between him and a man in Australia was discovered, Greater Manchester Police said.
The boy was already in police custody after having been arrested on April 2 at an address in Blackburn, northern England, on suspicion of preparing for an act of terrorism.
"We have uncovered communication between an individual in the North West and a man in Australia to what we believe is a credible terrorist threat," said Detective Chief Superintendent Tony Mole, from the North West Counter Terrorism Unit.
"The nature of the communication is currently under full assessment and subject to investigation," Mole said in a statement, adding there was no immediate threat to the public in Britain.
More than 200 police officers took part in the Australian raids on Saturday, the culmination of a month-long sting operation which led to five men aged 18 and 19 being detained.
Abbott said the authorities believed the group were involved in planning a terrorism attack against police on ANZAC Day, a national day of remembrance in Australia and New Zealand.
Australia has sent hundreds of soldiers to Iraq to help train forces fighting Islamic State, heightening concerns about reprisal attacks, and believes at least 70 of its citizens are fighting with the militant group which has seized swathes of territory in Syria and Iraq.
Likewise, British security services estimate some 600 Britons have joined the conflict in the region, including Mohammed Emwazi, dubbed "Jihadi John" by media, who has appeared in several Islamic State beheading videos.
Britain is also staging events to mark the Gallipoli campaign including a service of commemoration in central London on April 25, ANZAC Day, which Queen Elizabeth and her grandson Prince William are due to attend.
London police said forces around the country had been asked to review security plans around ANZAC Day events although there was no specific threat to ceremonies in Britain.
