Associated Press

Biden’s visit, the first to Angola by a U.S. president, is meant to promote billions of dollars of commitments to the sub-Saharan African nation for what he called the largest-ever U.S. rail investment overseas.

The corridor across southern Africa is meant to make it easier to ship raw materials for export and advance the U.S. presence in a region rich in critical minerals used in batteries for electric vehicles, electronic devices and clean energy technologies.

China already has heavy investments in mining and processing African minerals, and on Tuesday it announced it is banning exports to the United States of gallium, germanium, antimony and other high-tech materials. It came a day after the U.S. expanded its list of Chinese technology companies subject to controls.