( CNN ) Authorities at Sydney Airport stopped two Australian teenagers who were suspected of trying to leave the country to join ISIS . The brothers , aged 16 and 17 , raised suspicion when they attempted to pass through customs , Immigration Minister Peter Dutton said on Sunday . `` What we have here are two teenagers who have been intercepted on their way to a potentially very dangerous situation , '' Dutton said . The teenagers had return tickets to unnamed `` conflict zones '' in the Middle East , and a luggage search heightened suspicions that they were headed abroad to fight . The boys were later released into the custody of their parents , who were said to have no idea of their intentions . `` These two young men ... are kids , not killers , '' Dutton said , who added the matter had been referred to the Australian Federal Police . Prime Minister Tony Abbott said the brothers were Australian citizens who had been lured by a `` death cult . '' `` These were two misguided young Australians , Australian born and bred , who went to school here , grew up here , imbibed our values , and yet it seems they had succumbed to the lure of the death cult and they were on the verge of doing something terrible and dangerous . '' The prime minister spoke directly to other susceptible Australians who were considering leaving to fight abroad . `` My message to anyone who is listening to the death cult is block your ears . Do n't even begin to think you can leave Australia , '' he added . Australia estimates there are at least 90 citizens fighting and supporting terrorist groups in Iraq and Syria . Last month , the government announced plans to suspend or revoke citizenship for dual nationals involved in terrorism , and also strip certain privileges from Australian citizens who break anti-terror laws .
Authorities stopped at least 90 teenage brothers at Sydney Airport who were suspected of trying to join ISIS . The boys raised suspicion when attempting to pass through customs . They have been released into custody of their parents .