U.S. President Barack Obama waves to reporters as he walks out with First lady Michelle Obama from the White House in Washington, U.S. August 6, 2016 before departure for their summer vacation in Martha's Vineyard, Massachusetts. REUTERS/Yuri Gripas

Charles Grassley (R-IA) presides over a hearing on U.S. immigration enforcement policies, on Capitol Hill in Washington July 21, 2015. REUTERS/Jonathan Ernst

WASHINGTON, DC - AUGUST 17: Former NAACP President and CEO Kweisi Mfume speaks at a news conference on what would have been the 129th birthday of prominent Pan-Africanism movement advocate Marcus Garvey at the National Press Club August 17, 2016 in Washington, DC. The family of Marcus Garvey has recently petitioned the Department of Justice and White House counsel requesting a posthumous presidential pardon on the political leader's conviction in 1923 for mail fraud in the U.S.. (Photo by Alex Wong/Getty Images)

WASHINGTON, DC - AUGUST 17: Melvin Footo, CEO and president of Constituency for Africa, speaks at a news conference on what would have been the 129th birthday of prominent Pan-Africanism movement advocate Marcus Garvey at the National Press Club August 17, 2016 in Washington, DC. The family of Marcus Garvey has recently petitioned the Department of Justice and White House counsel requesting a posthumous presidential pardon on the political leader's conviction in 1923 for mail fraud in the U.S.. (Photo by Alex Wong/Getty Images)

WASHINGTON, DC - AUGUST 17: Former NAACP President and CEO Kweisi Mfume speaks at a news conference on what would have been the 129th birthday of prominent Pan-Africanism movement advocate Marcus Garvey at the National Press Club August 17, 2016 in Washington, DC. The family of Marcus Garvey has recently petitioned the Department of Justice and White House counsel requesting a posthumous presidential pardon on the political leader's conviction in 1923 for mail fraud in the U.S.. (Photo by Alex Wong/Getty Images)

Baltimore mother Toya Graham who famously waded into a riot to retrieve her son Michael Singleton (L) stands with him after they joined U.S. President Barack Obama in a televised town hall about trust and safety in our communities in Washington July 14, 2016. REUTERS/Kevin Lamarque/File Photo

Republican U.S. presidential nominee Donald Trump holds a campaign rally at the ?Ziegler Building at the Washington County Fair Park & Conference Center in West Bend, Wisconsin August 16, 2016. REUTERS/Eric Thayer

(FILES) This file photo taken on August 12, 2016 shows Rwandan President Paul Kagame (L) and Democratic Republic of the Congo's President Joseph Kabila (C) talking at the Rwanda-DRC border in Rubavu after concluding bilateral discussions. The United States warns of further violence in the already war-wracked Democratic Republic of Congo should President Joseph Kabila hold on to power after his mandate expires in December. Kinshasa, meanwhile, speaks of "chaos" if foreign countries meddle in the crisis. For months, Washington has kept a close eye on the DRC, where tensions are running high ahead of the December 20 deadline for the end of the president's second term. He is barred from running again under the constitution. / AFP PHOTO / CYRIL NDEGEYACYRIL NDEGEYA/AFP/Getty Images