The agreement, known as a “123 agreement,” completed together with what the Trump administration described as a “bilateral safeguards agreement.”

US Energy Secretary Chris Wright and Saudi Energy Minister Abdulaziz bin Salman formally signed the agreements.

The Trump administration released few details about the deal. However, the framework cleared the way for Saudi Arabia to build a uranium enrichment facility following a joint US-Saudi study, according to a person familiar with the matter who was not authorised to speak publicly and spoke on condition of anonymity, as cited in media reports.

“These agreements reflect our two nations’ shared commitment to strengthening U.S.-Saudi commercial relations, delivering prosperity at home and security to our allies abroad,” Wright said in a statement.

“Rest assured, these agreements uphold the highest standards of nuclear safety and nonproliferation, while relying on the world’s best nuclear technology and scientists, designed right here in the United States.”

Earlier, Secretary of State Marco Rubio sought to address criticism over the agreement while answering questions from reporters about concerns that helping Saudi Arabia enrich its own uranium could increase nuclear proliferation and competition in the region.

“The U.S. is not going to reach any agreement with any country in the world that leads to the risk of proliferation,” said Rubio, who was travelling in the Philippines on Wednesday.

According to a second person familiar with the decision, the agreement did not include the International Atomic Energy Agency's Additional Protocol, which allows for greater monitoring, inspections and verification.

The agreement is expected to remain in force for 30 years and involve US companies in developing the programme. The Department of Energy said the deal would be submitted to Congress for review, where lawmakers could oppose it.

Saudi Arabia's Energy Ministry said the agreement strengthened “efforts to diversify energy sources, advance cutting-edge technologies, and expand opportunities for cooperation and investment in ways that serve the mutual interests of the two friendly countries.”

The announcement came during the war launched by the United States and Israel against Iran, which they said aimed in part to eliminate Tehran's ability to develop a nuclear weapon. Iran has maintained that its uranium enrichment programme is peaceful.

Before the announcement, Alexander Bollfrass, a nuclear expert at the International Institute for Strategic Studies in London, described the agreement as “a revolutionary new approach” to nuclear nonproliferation policy.

“The revolutionary aspect of this agreement is that the United States is not asking Saudi Arabia to abide by the highest possible safeguards, internationally monitored safeguards that are standard and are available today, but instead is willing to at least theoretically transfer highly sensitive technology without the same level of oversight that one would expect,” Bollfrass said.

During his first term, President Donald Trump and former President Joe Biden both sought to reach a nuclear agreement with Saudi Arabia that would allow the kingdom to use American nuclear technology.

The agreement could allow Saudi Arabia to develop technology that nonproliferation experts said might eventually support a weapons programme.

Experts warned that operating uranium enrichment centrifuges inside Saudi Arabia could open the way to a future weapons programme. 

Crown Prince Mohammed bin Salman previously suggested the kingdom could pursue such a programme if Tehran acquired an atomic bomb.

Wright travelled to Saudi Arabia last year shortly before Trump's visit and discussed expanding the kingdom's commercial nuclear power industry with his Saudi counterpart. The US Department of Energy did not respond to multiple requests for comment.