Brandon-Lee and Tony-Lee Thulsie, 23, appeared briefly in the Johannesburg Magistrate's Court on Tuesday where the State submitted a provisional indictment to the court.
A female in the public gallery blew the pair a kiss as they walked down the dock.
They both face 11 counts including contravening the Protection of Constitutional Democracy Against Terrorist and Related Activities Act.
The State added the 12th count of fraud which was allegedly committed in the Free State in 2015.
According to the indictment handed over to the court: On August 9, 2015 at the magisterial district of Ficksburg in the Free State the accused "unlawfully and with intent to defraud, presented Lesotho passport[s] in the names of Christian Adam Leroy and Germain Adams Troy to department of home affairs manning [the] border post between South Africa and Lesotho as being their own valid passports".
The State further allege that the accused were aware that the passports were false, as well as their names.
Prosecutor Chris MacAdam asked the court to postpone the matter to May 15 in order to deal with the centralisation process of the fraud charge which is outside the jurisdiction of Gauteng.
In January, their case was postponed for further investigation.
At the time, their lawyer Annelene van den Heever argued that the case should be struck off the roll and that the State needed to get its house in order.
"This matter should be struck off the roll and reinstated when the State has more evidence to place the matter back on the roll," she said at the time.
The twins were arrested in July 2016 during raids in Newclare and Azaadville on the West Rand.
According to their charge sheet, the brothers, who were arrested along with siblings Ebrahim and Fatima Patel, were allegedly linked to the self-proclaimed Islamic State group and were allegedly planning to set off explosives at a US embassy and "Jewish institutions" in SA.
The investigating officer found the twins had been active on social media prior to their arrests, allegedly discussing matters that could incriminate them.