On 25 March 1969, Indonesian forces eliminated the Third Branch of the SPGF at Songkong in West Kalimantan following a two-day battle, wiping out the Sarawak People's Guerrilla Force's largest corps.
To replace the decimated SPGF, the Sarawak Communist Organisation created the North Kalimantan People's Guerrilla Force at Nonok on 13 July 1969.