Microsoft founder Bill Gates said most of his $200 billion (£150 billion) will go to improve African health and education services over the next 20 years.

"By unlocking human potential through health and education, every country in Africa should embark on the road to prosperity," the 69-year-old said.

Speaking at Addis Ababa, the capital of Ethiopia, he also urged young innovators in Africa to consider how to build artificial intelligence (AI) to improve health care on the continent.

Gates announced last month that he would donate 99% of his huge fortune by 2045 when his foundation plans to terminate its operations.

"I recently promised that my wealth will be given away over the next 20 years. Most of the funds will be used to help you deal with the challenges in Africa," he said in a speech at the headquarters of the African Union (AU).

Mozambique’s former first lady Graça Machel welcomed his announcement, saying it was in a “time of crisis.”

“We expect Mr. Gates to have a firm commitment to continue walking this transformation path with us,” she said.

The U.S. government cuts aid to Africa, including plans to treat HIV/AIDS patients, as part of U.S. President Donald Trump’s “America First” policy, raising concerns about the future of health care on the continent.

Gates said his foundation has a long history in Africa and it will focus on improving primary health care.

“What we learned is that during pregnancy, helping mothers stay healthy and achieving the best results,” he said.

“It will all be different to make sure the kids get good nutrition in the first four years.”

In a message to young innovators, the tech billionaire noted that cell phones have undergone radical changes in banking in Africa and believed that AI should be used now for the interests of the continent.

“Africa has largely skipped traditional banking and now, when you build the next generation of healthcare systems, you have the opportunity to think about how AI is built in,” he said.

Gates, who used Rwanda as an example, said it was already using AI-Sublable Ultrasound to improve services to identify high-risk pregnancy.

The Gates Foundation says there are three priorities: ending preventable deaths for mothers and babies, ensuring that the next generation grows up without having to suffer from deadly infectious diseases, and lifting millions out of poverty.

"At the end of 20 years, the foundation will sunset its operations," it said in a statement.

Last month, Gates said he would accelerate his donation through the foundation.

"When I die, people will say a lot about me, but I'm sure 'he died' won't be one of them," he wrote in his blog post.

According to Bloomberg, donating 99% of its wealth can still make the world's fifth-largest person a billionaire.

Gates, together with Paul Allen, founded Microsoft in 1975, and the company quickly became the dominant force in the software and other tech industries.

Gates has gradually withdrawn from the company in recent decades, resigned as CEO in 2000, and served as chairman in 2014.

He said investor Warren Buffett and other philanthropists had inspired him.

But his foundation critics say Gates uses his philanthropic status to avoid taxes and has had an undue impact on the global health system.