WASHINGTON (AP) — President Barack Obama and dozens of African leaders opened talks Wednesday on two key issues that threaten to disrupt economic progress on the continent: security and government corruption.

The discussions capped an unprecedented three-day gathering of African leaders in Washington. Much of the conference has centered on boosting U.S. financial ties with Africa, a continent that is home to six of the world's 10 fastest-growing economies and a rapidly expanding middle class.

As he has throughout the summit, Obama sought to highlight Africa's potential, particularly as an untapped trading partner for U.S. businesses. During remarks at the State Department, he said that even though the continent faces significant challenges, "a new Africa is emerging."

Yet White House officials acknowledge that security issues and governance challenges continue to constrain Africa's overall prosperity. There are particular concerns about Boko Haram, a violent Islamist group in Nigeria that was responsible for the kidnapping of more than 200 schoolgirls earlier this year.

Obama said the security discussions would center on ways to enable African governments to boost their own peacekeeping and counterterrorism capabilities while moving away from the need for costly outside intervention.

Leaders were also expected to discuss good governance and transparency, with U.S. officials arguing to their African counterparts that both are necessary conditions for economic growth.

The president acknowledged the ongoing Ebola crisis that is gripping three African nations, saying the affected countries have overcome great challenges in the past and are "drawing on that same spirit" now. The leaders of Liberia and Sierra Leone canceled plans to travel to Washington in order to deal with the crisis, while the president of Guinea is attending the talks.

The White House has promoted the summit as the largest-ever gathering of African leaders in the United States, with more than 50 countries represented. The leaders filled a large stage at the State Department for a group photo, with some wearing their country's traditional dress.

Obama was to close the summit with a late-afternoon news conference. First lady Michelle Obama was hosting a spouses' event with former President George W. Bush and his wife Laura.

On Tuesday, Obama announced $33 billion in U.S. commitments aimed at boosting financial ties with the continent. More than half was to come from the private sector, including Coca-Cola and General Electric.

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