U.S. Secretary of State Hillary Clinton said America stood by South Africa's diplomacy in Zimbabwe during her visit Friday to the country's capital, Pretoria.

"South Africa is very aware of the challenges in (Zimbabwe)," Clinton said during a media availability after meeting with South African President Jacob Zuma. "South Africa is deeply involved in trying to complete adherence to the global political agreement."

Clinton was in South Africa Friday as part of her seven-country, 11-day mission to the continent, CNN reported. She was in Kenya Thursday for an economic conference.

Zuma met with Zimbabwe's Prime Minister Morgan Tsvangirai this week to try to address concerns threatening to undermine the coalition government. South African leaders have been conducting quiet diplomacy with Zimbabwe for months.

Supporters of Zimbabwean President Robert Mugabe dismissed Clinton's comments as interference, saying Zimbabweans can resolve their problems internally.

After last year's disputed elections in Zimbabwe, Mugabe and Tsvangirai formed a unity government under an agreement mediated by South Africa.

South African Foreign Minister Maite Nkoana-Mashabane on Friday pledged to work with Zimbabwe to fast-track implementation of the power-sharing deal, CNN reported. She did not say what steps the South African government has taken to ensure this is done.