ADDIS ABABA, Ethiopia — Closing a historic visit to Africa, President Barack Obama on Tuesday urged the continent’s leaders to prioritize creating jobs and opportunity for the next generation of young people or risk sacrificing future economic potential to further instability and disorder.

He said the “urgent task” of generating jobs for a population that is expected to double to around 2 billion people in the coming decades will be “an enormous undertaking.” But he said it can be achieved with U.S. help.

“Africa will need to generate millions more jobs than it is doing now,” Obama said in a speech to the entire continent delivered from the headquarters of the African Union, a member organization of African nations. “And time is of the essence.”

“The choices made today will shape the trajectory of Africa — and therefore the world — for decades to come,” said Obama, who is seen by the people of Africa as one of their own. It was the first speech to the AU by a sitting American president.

The speech marked the end of a five-day visit to Africa that included an earlier stop in Kenya, homeland of Obama’s late father.

Obama also called on Africa’s leaders to make their countries more attractive to foreign investment by cleaning up corruption, upholding democratic freedoms, supporting human rights, and willingly and peacefully leaving office when their terms expire.

Obama, who is more than halfway through his second and final four-year term, said “I don’t understand this” phenomenon of leaders who refuse to step aside when their terms end. He referred to Burundi’s leader, who was just elected to a controversial third term although he is constitutionally limited to two. The announcement that President Pierre Nkurunziza was seeking a third term sparked days of unrest across the country.

“There’s a lot that I’d like to do to keep America moving, but the law is the law, and no one person is above the law, not even the president,” Obama said, adding that he thinks he could win if he were able to run again.

But he said he looks forward to a less restricted life when he leaves office.

“The point is, I don’t understand why people want to stay so long — especially when they’ve got a lot of money,” Obama said, an apparent reference to some previous African leaders who held tight to power while enriching themselves on government money.

He called on the AU to use its authority to help make sure African leaders stick to their term limits and follow their constitutions. “Nobody should be president for life,” said Obama, who leaves office in January 2017.

Africa’s progress will also depend on security and peace, since businesses and wealthy people won’t want to invest in unsafe places, the president said.

He pledged continued U.S. training assistance and other support in the fight against terrorism carried out across the continent by groups like al-Qaida, the Islamic State, al-Shabab and Boko Haram. He said the world must do more to help, too, and announced that he will host a summit at the United Nations in September to secure additional support for international peacekeeping, including in Africa.

Obama said Africa’s impending population boom could bring tremendous opportunities for the continent on the one hand.

“On the other hand,” he said, “we need only look to the Middle East and North Africa to see that large numbers of young people with no jobs and stifled voices can fuel instability and disorder.”