The Tonkin Expeditionary Corps was fully committed in Tonkin and northern Annam, while French troops in Cochinchina were busy dealing with an insurrection against the French protectorate in neighbouring Cambodia. In the early months of 1886 the insurgents took advantage of French weakness in the south to extend their influence into Khánh Hòa and Bình Thuận, the southernmost provinces of Annam. Cần Vương forces were now uncomfortably close to the French posts in Cochinchina, and the French authorities in Saigon at last responded.