Campaign 139 (14 September 1969–25 April 1970) was a major military offensive of the People's Army of Vietnam, launched against its Royalist enemies during the Laotian Civil War. Larger than previous invading forces, Campaign 139 was also a combined arms expedition containing tanks, artillery, engineers, and Dac Cong sappers. As such, it was a decided escalation in the war. It was also an exceptional rainy season offensive by PAVN, which usually withdrew during the wet season.