Within a few minutes of this, a whistle was blown from the Chinese side followed by medium machine gun firing against Indian troops from north shoulder. Due to the lack of cover in the pass, the Indian troops initially suffered heavy casualties. Shortly thereafter, the Chinese also opened artillery against the Indians. A little later, Indian troops opened artillery from their side. The clashes lasted through the day and night, for the next three days, with use of artillery, mortars and machine guns, during which the Indian troops beat back the Chinese forces. Five days after the clashes had started, an uneasy ceasefire was arranged. Due to the advantageous position Indian troops had because of their occupation of high grounds at the pass in Sebu La and Camel's back, they were able to destroy many Chinese bunkers at Nathu La.