The Pentagon's top general said recently that the U.S. Army's 1st Security Force Assistance Brigade (SFAB) will face a tough operating environment when it deploys to Africa, one that's much more austere than it faced in Afghanistan.

Chairman of the Joint Chiefs Gen. Mark Milley testified on the challenges that the SFAB will face in Africa before the House Armed Services Committee on Wednesday.

The Pentagon announced in mid-February that the specialized advisory unit will deploy to Africa to train local forces in an effort to contend with Russia and China in the region.

Rep. Anthony Brown, D-Maryland, asked for more information on the deployment since the commander of the 1st SFAB, Brig. Gen. Scott Jackson, said recently that the unit will not have the military infrastructure that was available in Afghanistan, such as the network of bases, supply chains and helicopters.

Related: Pentagon Ends Reviews of Niger Ambush that Killed 4 Soldiers

In 2017, a terrorist ambush on a 12-member Army Special Forces unit operating in a remote area of Niger left four American soldiers dead. The unit was accompanying 30 Nigerien forces on a mission to capture or kill a high-level Islamic State group leader in West Africa when more than 100 extremists launched a deadly attack near the village of Tongo Tongo.

"What are we doing to ensure that the SFAB has the infrastructure they need to do their job?" Brown asked.

U.S. Africa Command is currently assessing whether any changes need to be made to the military infrastructure in preparation for the SFAB's mission, Milley told Brown.

"Just so we are clear, though, the SFAB is not special operations forces; however, they are trained and explicitly selected to be able to operate in an expeditionary manner in a very austere environment," Milley said, describing how all of the SFAB members volunteered for such duty to train, advise and assist indigenous military forces. "The SFABs conduct a foreign, internal defense mission. They don't do all the other Special Forces missions, but they are capable of operating in very austere environments."

Brown said he understood Milley's point but did not accept the answer.

"Gen. Jackson made those comments because he has concerns about the infrastructure for logistics support that he will get while he is on the ground and, unlike what we demand in Korea and other places, we cannot ask African nations to foot the bill because they are broke," the lawmaker said.

Defense Secretary Mark Esper, who also testified at the hearing, said the SFAB will have what it needs to conduct its advise-and-assist mission in Africa.

"We are not going to put them out there without the means to do their job," he said.

The SFAB's upcoming deployment will allow the Army to return elements of an infantry brigade from the 101st Airborne Division to Fort Campbell, Kentucky, so it can focus on its primary job of training for combat.

The company-sized element of the 101st deployed to Kenya in early January as part of the East African Response Force (EARF) after an attack by al-Qaida affiliate al-Shabaab on a base in Kenya killed one U.S. soldier and two American contractors.

The recent shifting of forces is the result of a review Esper has ordered to assess how each of the combatant commands is organized and equipped to support the National Defense Strategy.

Rep. Trent Kelly, R-Mississippi, told Esper and Milley that he just returned from a trip to Africa with Rep. James Inhofe, R-Oklahoma, to meet with local leaders and military commanders.

"We do not need to reduce the number of troops that we have there," Kelly said. "I think we have some real threats -- both terrorists and great power competition -- in that region, and I just think that we need to be judicious in making sure we don't reduce the amount of troops there."

The U.S. currently has roughly 6,000 troops based in Africa.

In a Jan. 10 statement, Inhofe said that troop withdrawals from Africa would be "short-sighted" and could cripple AFRICOM's ability to execute its mission.

Esper told lawmakers at the hearing that news reports of a planned withdrawal of U.S. forces from Africa are not accurate.

"There are no plans to completely withdraw all forces from Africa. That has been misreported and repeated over and over again," he said. "But what I am looking to do is to make sure I can resource the missions that are absolutely required and to right size the force."

-- Matthew Cox can be reached at matthew.cox@military.com.

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