Australia has raised its terror alert level to `` high '' for the first time since the national alert system was introduced in 2003 . According to the four-level system , a reading of `` high '' means a terrorist attack `` is likely , '' however the country 's Prime Minister Tony Abbott said no specific threat had been made . `` This does not mean a terror attack is imminent , we have no specific intelligence of particular plots . What we do have is intelligence that there are people with the intent and capability to mount attacks , '' Abbott said at a press conference in Canberra on Friday . What does `` high '' mean ? Australia introduced its alert system in 2003 , with four levels of risk : low , medium , high and extreme . It 's been at `` medium '' since the system began , and is defined as meaning a `` terrorist attack could occur . '' The elevation to `` high '' would not make much difference to daily life for most people , the prime minister said . `` What people would probably notice though is more security at airports , more security at ports , more security at military bases , more security at government buildings and more security at large public events , '' he said . Why now ? The decision to raise the level was foreshadowed by the departing director-general of the Australian Security Intelligence Organization ( ASIO ) earlier this week . David Irvine said the threat level had been building in Australia over the last year , due to the increasing influence of jihadists fighting for Islamic extremists ISIS in the Middle East who had recruited Australians to fight . `` They are of concern because , if they come home , they come home with training and with potentially increased intent , '' he told the ABC . Officials believe there are at least 60 Australians fighting with terror group ISIS , and as many as 100 `` facilitators '' still in the country . A number of arrest warrants have been issued for suspected terrorists fighting abroad , and police have swooped on a number of suspects in Australia , most recently arresting two men in Brisbane for allegedly recruiting and funding fighters sent to Syria . Alert levels elsewhere . Australia 's higher alert level follows an increase in the United Kingdom , which raised its level from `` substantial '' to `` severe '' in late August . Again , authorities said there was no intelligence to suggest an attack was imminent . However , hundreds of British citizens are believed to have joined jihadists abroad . Notably , a hooded man with a British accent appeared to be the executioner of U.S. journalists James Foley and Steven Sotloff on videos released by ISIS . The U.S. replaced its color-coded warning system with the National Terrorism Advisory System ( NTAS ) in 2011 . NTAS alerts are only issued if there 's `` credible information about a threat . '' And , alerts are classified as either `` elevated '' or `` imminent . '' France abandoned its color-coded alerts earlier this year , and instead now relies on a two-level `` Vigipirate '' system . When more vigilance is needed , the triangle logo is displayed in public places . If there 's specific intelligence of an attack , the logo carries the words `` alerte attentat '' or `` attack alert . '' MAP : Where is ISIS in Iraq ? MAP : Where do jihadis come from ?
Australia increases terror alert level for first time in 11 years . The Australian government has raised its terrorism threat to the highest level, warning of a possible attack on public transport and other targets within days. However , PM says no specific threat has been made .