The United States urged African leaders on Monday to respect political differences, saying that core democratic principles are vital to achieving long-term economic growth.
The call came at the start of an unprecedented US-Africa summit in Washington attended by 35 presidents, nine prime ministers, three vice presidents, two foreign ministers and a king.
The three-day program of talks marks one of President Barack Obama's biggest initiatives for Africa, against the backdrop of an Ebola outbreak and several security crises on the continent.
Washington is seeking stronger economic ties with Africa, having found itself outpaced by China and Europe on a continent where the International Monetary Fund expects to see 5.4 percent growth this year and 5.8 the next.
But, in a sharp contrast to China's business-first approach, US leaders first addressed democracy and civil rights concerns.
Vice President Joe Biden met African civil rights leaders and encouraged them to fight corruption.
"It's a cancer in Africa as well as around the world. Widespread corruption is an affront to the dignity of its people and a direct threat to each of your nations' stability, all nations' stability," Biden said.
- More than 'strong men' -
Secretary of State John Kerry said that a strong civil society can bolster democracy and the rule of law -- which are "not just American values, but universal values."
"Diversity is always a better predictor of success than uniformity. Because strong institutions are always more effective, more durable and more predictable than strong men or women," he said.
Outside the State Department a crowd of around 100 protesters, many from Washington's large expatriate Ethiopian community, demanded the United States not cosy up to African autocrats.
Citing the example of South Africa's late anti-apartheid champion Nelson Mandela, Kerry said that most Africans supported limiting their leaders to two terms in office.
"We will urge leaders not to alter national constitutions for personal or political gain," Kerry said.
But Kerry did not directly name any of the long-serving leaders-- most of whom were nonetheless invited to the summit including Equatorial Guinea's Teodoro Obiang Nguema, Rwanda's Paul Kagame, Uganda's Yoweri Museveni or Cameroon's Paul Biya.
Angolan President Jose Eduardo dos Santos, in office for 35 years, was also invited but sent the vice president.
Earlier Mondya, Kerry met with President Joseph Kabila of the Democratic Republic of Congo and welcomed his efforts to tackle militia violence in the war-torn nation.
The United States has been pushing Kabila to step down in line with his constitutional limit when the vast nation goes to the polls again in 2016.
The top US diplomat also vowed that the United States would support the work of embattled gay activists and champion press freedom "including for journalists charged with terrorism or imprisoned on arbitrary grounds."
Ethiopia has recently charged seven bloggers and three journalists with terrorism. Ethiopian Prime Minister Hailemariam Desalegn -- a key security partner -- was nevertheless invited.
- Ebola outbreak -
While the United States had hoped to focus on an economic agenda, the public health crisis caused by the Ebola outbreak -- which has left almost 900 people dead in west Africa since the start of the year -- is also taking center stage.
On the sidelines of the summit, Guinean President Alpha Conde and senior officials from Liberia and Sierra Leone held talks on the Ebola response with Tom Frieden, the director of the US Centers for Disease Control and Prevention, and Sylvia Mathews Burwell, the US secretary of health and human services.
Security officials were expected to focus on instability in South Sudan and the Central African Republic and to discuss ways to act against Al-Qaeda in the Islamic Maghreb, Boko Haram militants from Nigeria and Shebab militants from Somalia.
And, despite strong growth in much of Africa, Ghana's President, John Mahama, said that he is seeking an IMF bailout to address a currency plunge and close a large fiscal deficit in what was once one of Africa's healthiest economies.
-Greater involvement by Obama -
Obama, who plans personal involvement Tuesday and Wednesday at the summit, is the first US president of African descent but devoted little time in his first term to the continent.
He traveled last year to Africa and announced an initiative to bring electricity to at least 20 million more Africans through $7 billion in private funds. But officials have warned observers not to expect flashy announcements from the summit in Washington.
South African President Jacob Zuma said he believed Obama's African background "has not helped" as he faces domestic political pressure in the United States not to put more focus on Africa.
"I believe he could have done more, but I think he always was aware of this fact, and therefore he has navigated the situation very well," Zuma told reporters.