US President Donald Trump made the announcement Tuesday, specifying that Washington would soon re-impose "the highest level of economic sanctions" on Iran.
The deal, formally known as the Joint Comprehensive Plan of Action (JCPOA), signed between Iran, the five permanent members of the UN Security Council (China, the United States, Britain, France and Russia), Germany and the European Union (EU) in 2015, froze the Iranian nuclear program in exchange for a gradual normalization of economic and political relations with the international community and the end of sanctions.
"As a matter of principle, and deeply rooted in its foreign policy, South Africa supports multilateral diplomacy and the peaceful resolution of conflict," said Ramaphosa.
The JCPOA is a significant achievement in this regard, which provides a framework of confidence under which Iran can pursue the development of its nuclear capabilities for civilian purposes, Ramaphosa said.
In addition, the agreement was unanimously endorsed by the UN Security Council in resolution 2231, which establishes a binding legal framework to resolve the dispute over Iran's nuclear program, the president said.
"It is important that the progress made over many years of negotiation should not be lost," Ramaphosa said.
Since its adoption, the JCPOA has contributed significantly to the reduction of tensions over Iran's nuclear program and still has an important role to play in promoting peace, stability and the normalization of relations, said Ramaphosa.
In the interest of regional and international peace and security, the South African government calls on the other parties of the JCPOA to continue to honor their commitments under the agreement, he said.
"In this regard, the decision of the United States should not prevent the remaining parties from honoring their commitments, nor should it impact negatively on the relevant structures and mechanisms created by the JCPOA," the president added.