WASHINGTON — Al Qaeda’s affiliate in North Africa is operating terrorist training camps in northern Mali and providing arms, explosives and financing to a militant Islamist organization in northern Nigeria, the top American military commander in Africa said on Monday.

The affiliate, Al Qaeda in the Islamic Maghreb, has used the momentum gained since seizing control of the northern part of the impoverished country in March to increase recruiting across sub-Saharan Africa, the Middle East and Europe, said the commander, Gen. Carter F. Ham.

General Ham’s assessment is the most detailed and sobering American military analysis so far of the consequences of the Qaeda affiliate and associated extremist groups seizing the northern part of Mali to use as a haven.

“As each day goes by, Al Qaeda and other organizations are strengthening their hold in northern Mali,” General Ham said in remarks at the Homeland Security Policy Institute at George Washington University. “There is a compelling need for the international community, led by Africans, to address that.”