EXCLUSIVE
POLICE fear young Australians are returning from the bloody Syrian battlefield better equipped to carry out attacks on home soil, but have limited evidence to prosecute them.
NSW Police Counter Terrorism boss Catherine Burn says police are worried about the number of Australians who may be returning from declared no-go zones with the desire to carry out attacks here. 
Ms Burn said authorities were facing a constant challenge when it came to proving that radicals had visited conflict zones.
"That's something that we face quite regularly with this environment that we're in, and it is a -concern," Ms Burn said.
"We say, like my Australian Federal Police colleagues, that of course we're worried. Because if they have been in Iraq or Syria and they have been joining in hostilities, they might come back with a greater capability and greater desire to do something here. It is difficult for us to obtain evidence from places like Iraq and Syria.
"We do know there are people who have returned to Australia from those areas. We're aware of that." Under federal government legislation, Australian citizens cannot travel to declared "no-go" zones in Islamic State strongholds of Raqqa and Mosul. Police are aware of at least 30 Australians who have returned home from the conflict zone but have not been prosecuted because there is a lack of evidence or they travelled there before IS was declared a terrorist organisation.
Meanwhile, NSW Police held meetings with FBI agents specialising in counter terrorism behavioural analysis in Sydney two weeks ago. Ms Burn said the US agents urged police to focus their attention on families and communities, because in 84 per cent of terror cases in the US, family or friends had seen the warning signs.
Police in Australia have foiled six terror plots in just over a year, -including an alleged plan to behead a member of the public in Sydney.Ms Burn travelled to Paris in the wake of the Charlie Hebdo attacks for briefings with authorities. She said there was no specific threat to Australia after the latest horrifying attacks in France, but said there were people in Australia with the "intent" to cause harm.