Yellen spoke to reporters alongside South African Finance Minister Enoch Godongwana in Pretoria on the third leg of her nearly two-week tour of Africa, and just days after Russian Foreign Minister Sergei Lavrov visited South Africa.

In prepared remarks, Yellen welcomed Godongwana's "cooperation and insightful views" in their talks so far, and said she planned to raise several issues, including Zambia's stalled sovereign debt restructuring effort, given South Africa's key role on the country's creditor committee.

"The United States strongly values our relationship with South Africa," Yellen said in remarks that included no mention of Russia or China, or White House concerns about Pretoria's plans to hold joint military drills with both countries.

The U.S. Treasury issued no statement about Yellen's closed-door meeting on Wednesday with South African President Cyril Ramaphosa, a meeting described by Pretoria as a "courtesy call."

South Africa has remained one of Moscow's most important allies on a continent divided over Russia's invasion of Ukraine on Feb. 24.

Yellen's trip kicked off a yearlong charm offensive of U.S. top leader visits to Africa aimed at deepening U.S. economic ties with the continent and countering China's long dominance of trade and lending with many African nations.

Throughout her visit, Yellen has emphasized the right of countries to choose their trading partners, while pitching the greater transparency and lasting nature of engagement with the United States.

The Treasury secretary, who meets with South Africa's central bank governor later on Thursday, singled out South Africa's "Just Energy Transition Partnership," which was backed in late 2021 by the United States, Britain, France, Germany and the European Union. They pledged a combined $8.5 billion to accelerate South Africa's transition away from fossil fuels to renewable energy, but the total bill will be much higher.

"This partnership represents South Africa's bold first step toward expanding electricity access and reliability and creating a low carbon and climate resilient economy," Yellen said, adding that it would "alleviate the deep fiscal strain the energy sector is putting on South Africa's economy."

(Reporting by Andrea Shalal in Pretoria; Editing by Matthew Lewis)

By Andrea Shalal