Fatima Patel and Sayfydeen Aslam del Vecchio are alleged to have snatched British holidaymakers Rod, 73, and Rachel Saunders, 64, both renowned botanists, in KwaZulu-Natal province last month.
The Saunders are still missing. Since their disappearance, 734,000 rand (USD 62,000) has reportedly been drained from the couple's accounts and their Toyota Land Cruiser was found covered in blood.
Patel, 27, and Del Vecchio, 38, appeared briefly alongside Themba Xulu who faces lesser charges in connection to the case.
Patel wore an Islamic face covering and stood beside Del Vecchio who brought a Koran into court, the Times LIVE news site reported.
Also Read
The pair, who face the more serious terrorism charges, are alleged to have hoisted an Islamic State flag in a reserve in the region where the Saunders disappeared.
Del Vecchio also faces a charge relating to activities on an extremist web forum.
Xulu was allegedly found to have mobile phones that belonged to the Saunders in his possession.
Following the disappearance of the Saunders, who live in Kenilworth near Cape Town, the British foreign ministry warned that "terrorists are likely to try to carry out attacks in South Africa".
"The main threat is from extremists linked to Daesh (formerly referred to as ISIL). In February 2018, two South African-British nationals were kidnapped," it said in travel advice for South Africa.
The advisory said that some South Africans who had visited Syria, Iraq and Libya were "likely to pose a security threat on their return".
"There's also a threat from individuals who may have been inspired by terrorist groups, including Daesh," it added.
The US and Britain warned in 2016 of the possibility of attacks by jihadist extremists in South Africa's major cities.
The country has so far been spared the jihadist attacks that have struck several other countries on the continent.
"We do not have an imminent threat from terrorism in our country, our law and enforcement agencies remain vigilant," said Ramovha.
Disclaimer: No Business Standard Journalist was involved in creation of this content