Soon afterwards, Indian and Chinese forces clashed again in the Cho La incident. On 1 October 1967, some Indian and Chinese soldiers had an argument over the control of a boulder at the Chola outpost in Sikkim (then a protectorate of India), triggering a fight that escalated to a mortar and heavy machine gun duel. On 10 October, both sides again exchanged heavy fire. While Indian forces would sustain eighty-eight troops killed in action with another 163 troops wounded, China would suffer more casualties, with 300 killed and more than 200 wounded in Nathu La, as well as forty in Cho La.