PRETORIA-- South African President Cyril Ramaphosa has voiced his regret over United States President Donald Trump's decision to pull out the US of the nuclear deal with Iran.

On Tuesday, President Donald Trump announced the decision to withdraw from the Iran nuclear deal, specifying that Washington would soon re-impose "the highest level of economic sanctions" on Iran.

The deal, known as the Joint Comprehensive Plan of Action (JCPOA), was signed between Iran, the five permanent members of the United Nations Security Council -- China, Britain, France, Russia and the US -- plus Germany and the European Union (EU) in 2015.

The agreement froze the Iranian nuclear programme in exchange for a gradual normalisation of economic and political relations with the international community and the end of sanctions. It was unanimously endorsed by the United Nations Security Council in Resolution 2231, which establishes a binding legal framework to resolve the dispute over Iran's nuclear programme.

President Ramaphosa said the JCPOA represents a major achievement in nuclear non-proliferation and diplomacy, and has contributed to regional and international peace and security. It provides a framework of confidence under which the Islamic Republic of Iran can pursue the development of its nuclear capabilities for civilian purposes, he said Wednesday.

It is important that the progress made over many years of negotiation should not be lost. Since its adoption, the Joint Comprehensive Plan of Action has contributed significantly to the reduction of tensions over Iran's nuclear programme and still has an important role to play in promoting peace, stability and the normalisation of relations.

In the interest of regional and international peace and security, President Ramaphosa said the South African government calls on the other parties of the JCPOA to continue to honour their commitments under the agreement.

The decision of the United States should not prevent the remaining parties from honouring their commitments, nor should it impact negatively on the relevant structures and mechanisms created by the JCPOA, President Ramaphosa said.