WASHINGTON—The Pentagon will deploy approximately 300 U.S. Marines to Helmand province in southern Afghanistan beginning in the spring, the Marines said Friday, a return of those forces to a region where they previously engaged in heated combat.

The troops will be the first Marines in Helmand since 2014.

Replacing a U.S. Army contingent, the Marines will serve as advisers to Afghan soldiers and police officers fighting Taliban forces. A few dozen Marines and Navy personnel are currently deployed in the north of the country, where they are joining with forces from the country of Georgia in guarding Bagram Air Field.

Marines left Helmand in 2014 when their combat mission ended and they turned over their major base there, Camp Leatherneck, to the Afghans. At least some of the Marines will head back to Leatherneck, the Corps said.