The 17-year-old Australian teen detained during raids in Melbourne earlier this year has pleaded guilty for planning a terrorist attack between 25 April and 8 May.

The boy, whose name is not known, was due to face a committal hearing in a children's court on Monday, but admitted to one charge and the prosecutors dropped the two other charges, BBC reported.

In previous hearings, the court was told the teen obtained instructions for making explosives online, BBC reported.

The boy did not appeal for bail and has been remanded in judicial custody. He will appear in court again on Thursday.

The boy's computer contained encrypted documents on how to make bombs; the police have also seized pressure cooker and pipes connecting the caps, according to the Australian Broadcasting Corporation.

Last week, the Australian Police has arrested a 20-year-old man and a 15-year-old boy for conspiracy. The duo were planning to attack government buildings, but were arrested by the counter-terrorism police in Sydney.

Three other men, who were part of the same operation, are currently in custody on terrorism-related charges, according to Reuters.

An ally of United States in their fight against the Islamic State, the island continent has been on heightened alert for attacks by "home-grown radicals since 2014", Reuters reported.

According to the police, the incidents have raised concern about the efficiency of the government in dealing with the youths at risk in the Muslim population.

Last year, a teenager stabbed two counter-terrorism officers. He was later shot dead. In the same year, two hostages were killed when the police raided a Sydney café to end a 17-hour siege by gunmen, as reported by Reuters.