South African President Cyril Ramaphosa has demanded the immediate release of at least three compatriots, including Nelson Mandela's grandson, held by Israeli forces after a humanitarian aid convoy to Gaza was intercepted overnight, branding the detentions an "abduction" that tramples global solidarity.

The Global Sumud Flotilla, carrying 40 activists and supplies from around the world, aimed to pierce Israel's naval blockade when Israeli ships halted most vessels Wednesday, escorting them to Ashdod port for immigration checks without lawyers present.

Adalah, the legal aid group, gained access later Thursday for consultations, but the fate of the crew remains in limbo.

Among the detained are Nkosi Zwelivelile "Mandla" Mandela and two others, with three more South Africans' involvement unconfirmed, per the presidency.

One vessel, the Mikeno, slipped into Palestinian waters, though contact has gone dark.

Ramaphosa slammed the action as "another grave offence," urging swift resolution amid escalating scrutiny of Israel's Gaza siege.

The flotilla's bid highlights persistent aid blockades, where UN reports flag famine risks for 2.1 million in Gaza.

South Africa's vocal stance—having hauled Israel to the ICJ over genocide claims—adds diplomatic weight, with Ramaphosa vowing no letup on his citizens' behalf.

As activists languish in Ashdod, the standoff tests Israel's blockade policy, drawn since 2007, against international calls for access. Pretoria's plea underscores a rift, where humanitarian intent clashes with security red lines in a conflict that has claimed over 41,000 Palestinian lives since October 2023.