Johannesburg - Two brothers allegedly linked to ISIS (Islamic State) were planning to set off explosives at a US embassy and "Jewish institutions" in South Africa, according to their charge sheet at the Johannesburg Magistrate's Court on Monday.Brandon-Lee and Tony-Lee Thulsie, both 24, face terrorism-related charges.Two others who were arrested with them in Newclare and Florida were expected to appear in the Kagiso Magistrate's Court later on Monday."The accused unlawfully and intentionally conspired to commit the crime of terrorism by planning to cause explosions at a Mission of the United States of America and Jewish institutions (all such structures located in the Republic of South Africa) in order to endanger life, cause death and/or serious bodily harm and the destruction... to such structures," the charge sheet against the brothers read."Such conspiracy and incitement was intended to cause and spread feelings of terror, fear or panic in the civilian population of South Africa and particular the US and Jewish sector thereof and to intimidate the government of the United States of America."Such conspiracy and incitement was directly or indirectly in whole or part to further the political, religious or ideological motives and objectives of an international terrorist organisation which has been designated by the security council of the United Nations, namely the Islamic State in Iraq and the Levant (ISIL, also known as Da'esh and ISIS)."Case postponedThe two bearded brothers sat closely together while in the dock at the Johannesburg Magistrate's Court on Monday. The courtroom was packed with their family and friends.Brandon was wearing a grey hoodie and had a black kufi on his head. His brother was wearing a black thawb.The brothers responded softly when the judge asked if they spoke English.The case against the two was postponed to July 19, and they remain in custody.Brandon blew a kiss to his mother as the pair made their way down the stairs to the holding cells. Their mother, who was crying, left the courtroom in a hurry while being comforted by family members.The charge sheet said the brothers also allegedly tried to leave the country to join Isis in Syria in April 2015.Hawks spokesperson Brigadier Hangwani Mulaudzi said on Sunday that the arrest of the four followed prolonged investigations into possible terror related activities in the Johannesburg area.Plans to join ISISThe National Intervention Unit, the bomb squad and other law enforcement agencies aided in the arrests, Mulaudzi added.He said the four were identified after they attempted to travel to Syria in 2015."Investigations showed they intended to join terrorist group Isis," Mulaudzi told News24 at the weekend.According to Mulaudzi, the Hawks swooped on the suspects' locations, seizing several items for analysis.Hawks national head, Lieutenant-General Mthandazo Ntlemeza, said the arrests were a "very big step forward in the fight against terrorism"."But we cannot say that the problem has been solved. [These] terrorist organisations are recruiting in our country... law enforcement agencies will continue to work around the clock to prevent any form of recruitment on our soil."Ntlemeza said authorities would remain on high alert."We will diffuse any attempts to form any terrorist groups in our country. Our people should also be vigilant and report any suspicious activities to the police," he said.