STUTTGART, Germany (NYTIMES) - Hundreds of US troops in Africa would be reassigned and the number of Special Operations missions on the continent would be wound down under plans submitted by a top military commander, a response to the Trump administration's strategy to increasingly focus on threats from China and Russia.

Defence Department officials said they expected most of the troop cuts and scaled-back missions to come from Central and West Africa, where Special Operations missions have focused on training African militaries to combat the growing threat from extremist Islamic militant groups.

The plan by General Thomas D. Waldhauser, the leader of US Africa Command, follows an ambush in Niger late last year that killed four American soldiers and an attack in southwestern Somalia that killed another in June.

In an interview with The New York Times, General Waldhauser said his plan would help streamline the military's ability to combat threats around the world - but not retreat from Africa.

"We're not walking away," he said at his Germany headquarters last week, adding that the United States would still "reserve the right to unilaterally return" to protect American interests.

Africa has increasingly become an emerging battlefield for the United States in the fight against Islamic militant groups, including the Islamic State, Boko Haram and others across the continent that have sworn loyalty to al-Qaeda.

None of the offshoots of those groups have directly attacked the United States from Africa. But the Pentagon has for years sought to train local forces to deal with Islamic extremists in Africa - in part to distance the United States from any threats brewing on the continent.

Carter F. Ham, a retired Army general who once led Africa Command, said he agreed "in principle" with paying more attention to Russia and China - the notion at the heart of a national defence strategy unveiled in January by Defence Secretary Jim Mattis.

But, Ham said, "my concern in Africa is that with an already very modest presence and level of engagement, reducing that will lessen the likelihood for good outcomes across the continent." Africa receives a small portion of Pentagon investment compared with Germany, South Korea and Japan, for instance.

General Waldhauser said Africa Command was the first to be asked to submit a drawdown plan, as The Times initially reported in June. But he said he expected other American combatant commands around the world to do the same under the defence strategy to better position the US military against threats from Russia, China, Iran and North Korea.

The strategy represented a shift from fighting terrorism to countering state threats. When he announced it in January, Mr Mattis declared that "we will continue to prosecute the campaign against terrorists, but great power competition - not terrorism - is now the primary focus of US national security." The drawdown in Africa, General Waldhauser said, will include the departure of hundreds of Special Operations troops and their support forces. It will begin in places like Cameroon, where American war planners believe their efforts to train that country's special operations forces have been largely successful. The United States has about 300 troops in Cameroon.

General Waldhauser said Cameroon's security forces have improved to the point where they no longer need Americans to accompany them on missions.

"They can do it on their own," he said. "That would be an example of a country where we have worked ourselves out of a job." A Defence Department official said Nigerien forces are also considered to be improving to the point where they may soon not need American help.

But it was in Niger in October where four American soldiers, their translator and four Nigerien troops were killed when their convoy was attacked near the border with Mali. A Pentagon investigation into the attack found a "general lack" of "command oversight at every echelon."

Mr J. Peter Pham, an Africa specialist at the Atlantic Council in Washington, said that too many US Special Operations forces - especially in places like Somalia - could lull local officials into complacency and dependency, preventing them from getting their own soldiers up to speed.

"Islamist terror threats are indeed on the rise on the continent, but that doesn't mean that every Islamist terrorist needs to be hunted down by US Special Forces," Mr Pham said.

Still, he added, "great power competition also happens in Africa," and pointed to a recent tussle between the United States and China, both of which have major military bases in Djibouti. The United States complained in May that Chinese nationals pointed lasers at US military aircraft near Djibouti, a charge strongly disputed by Beijing.

More than 7,300 Special Operations troops are working around the world, many of them conducting shadow wars against terrorists in Yemen, Libya, Somalia and other hot spots. About 1,200 of those troops are on missions in Africa, and they are facing the most immediate drawdown.

As part of the plan, the Africa Command was asked how it would conduct its counterterrorism missions if the number of US commandos there was cut by 25 per cent over 18 months, and by 50 percent over three years.

Ultimately, that would leave about 700 troops - roughly the same number as in 2014, according to data from Africa Command's special operations branch. By comparison, there were 70 Special Operations troops on the continent in 2006.

General Waldhauser said the cuts, which top officials in Washington are reviewing, will not be that deep for Army Special Forces known as Green Berets. But he declined to give specific figures, citing classification restrictions.

Even before Mr Mattis' directive, the Special Operations Command had begun to rely on conventional troops for some of the missions it had taken on since the Sept. 11, 2001, attacks. In places where Special Operations troops are frequently in combat, such as Afghanistan and Syria, regular soldiers and Marines are sometimes attached to commando units for security or firepower.

General Waldhauser said that in Africa, state National Guard units - from California, Michigan and Indiana - could be paired with African militaries as Special Operations units draw down.