Caskets carrying the remains of three Army Green Berets will arrive in coming days at the military’s mortuary in Dover, Del.

That much is certain.

Less clear are the circumstances surrounding their deaths Wednesday in an ambush in the Central African country of Niger, and the precise nature of their mission. The Pentagon and the White House have long sought to frame the U.S. military’s activities there as providing support for U.S. allies battling extremists throughout the region — and being removed from direct combat.

That appears to be changing, observers said. “Training operations have picked up in recent years, and with this incident, the U.S. seems to be getting closer and closer to combat operations,” said Andrew Lebovich, a visiting fellow at the European Council on Foreign Relations.

U.S. forces have expanded efforts in Niger, military officials have said, as part of a growing presence in the Sahel region. The vast expanse of desert stretches across the continent, and affiliates of Al-Qaida and the Islamic State of Iraq and Syria have taken advantage of instability in Libya, where arms and fighters flow into a region difficult to govern.

About 645 U.S. personnel were assigned to posts in Niger as of June, about 300 to the south in Cameroon. Lebovich said the numbers could be even higher now. This expansion is a potential tension point for President Donald Trump, who has sought to facilitate the Pentagon’s counterterrorism objectives while calling for scaling back the U.S. military global footprint because his political base does not see such missions as vital to the national interest.