Liberian Vice President Joseph Nyuma Boakai (R) speaks at a discussion on "Empowering Africa's Youth: Lessons From Liberia" in Washington D.C., capital of the United States, Aug 4, 2014. A discussion on "Empowering Africa's Youth: Lessons From Liberia", a side event of US-Africa Leaders Summit, was held here on Monday. [Photo/Xinhua]

"It's a cancer in Africa as well as around the world," Biden said. "Widespread corruption is an affront to the dignity of its people and a direct threat to each of your nations' stability, all nations' stability."

"It not only undermines, but prevents the establishment of genuine democratic systems," he remarked. "It stifles economic growth and scares away investment."

The Obama administration set four strategic objectives in its new strategy toward sub-Saharan Africa unveiled in June 2012 -- strengthening democratic institutions; spurring economic growth, trade and investment; advancing peace and security; and promoting opportunity and development.

On the occasion, Kerry also called for the defense of rule of law and human rights. "We will urge leaders not to alter national constitutions for personal or political gain," he said.

The White House does not arrange any bilateral meetings between Obama and the African leaders, while Kerry met on Monday with presidents of the Democratic Republic of Congo, Burundi, Burkina Faso and Mauritania, vice president of Angola as well as prime ministers of Libya and Egypt.

The raging Ebola epidemic hitting West African countries hard have prevented the presidents of Liberia and Sierra Leone from attending the Washington summit and overshadowed the event amid fear of spread.

While addressing a press conference at the White House on Friday, Obama said his administration was taking Ebola "very seriously" and would do screening on African delegations. "We feel confident that the procedures that we've put in place are appropriate."

The deadly Ebola virus has sickened around 1,600 people and killed some 900 since March.

US Secretary of Health and Human Services Sylvia Burwell and Director of the Centers for Disease Control and Prevention Tom Frieden on Monday met with Guinean President Alpha Conde and senior officials from Liberia and Sierra Leone on the outbreak of Ebola in their region.

"The group identified national and regional priorities and held intensive discussions on the types of assistance needed to mount an effective response," the State Department said in a statement.

"Secretary Burwell and Director Frieden reiterated US engagement and support for efforts to control the outbreak and address the challenge," said the statement.

White House spokesman Josh Earnest said Monday that the US would not turn back flights from West Africa over concerns about Ebola.

"There are in place a lot of precautions to ensure the safety of the American public and of the traveling public," he told a daily press briefing.