Secretary of State John Kerry says the United States supports African-led efforts to combat "the most deadly conflicts of the continent."
He said Thursday during his visit to Addis Ababa, that too many nations are at risk of descending into broad-based violence.
"It is clear that the unspeakable violence in the Central African Republic, the deliberate killing of civilians on both sides in South Sudan, both of those underscore the urgency of the work that we have to do together."
Kerry visited the African Union's headquarters in the Ethiopian capital for talks with officials on the C.A.R., where Muslims continue to flee their homes to escape attacks by Christian militia.
Earlier Thursday he met with the foreign ministers of Ethiopia, Uganda and Kenya to discuss the challenges of how to get South Sudan's warring sides to halt their months of deadly fighting. The top diplomats agreed that South Sudan needs a legitimate force to help stabilize the country.
The United States has already threatened travel and financial sanctions against those responsible for violence that has displaced more than a million people.
Kerry said the United States will also help Nigeria deal with Islamist militants blamed for thousands of deaths.
"We'll also continue to provide counter-terrorism assistance to help Nigerian authorities to develop a comprehensive approach to combat Boko Haram, while at the same time respecting civilians and respecting human rights."
While in Addis, Kerry is due to meet with Somali President Hassan Sheikh Mohamud to discuss the fight against the al-Qaida-linked militant group al-Shabab.
On Saturday, he travels to the Democratic Republic of Congo's capital to meet with President Joseph Kabila. The two will discuss recent security gains against rebel groups in volatile eastern Congo.
After a stop in Angola, Kerry returns to Washington on Monday.