At the time of the partition of India in 1947, the Dogra ruler Maharaja Hari Singh signed the Instrument of Accession to India. Pakistani raiders from Gilgit had reached Ladakh and military operations were initiated to evict them. The wartime conversion of the pony trail from Sonamarg to Zoji La by army engineers permitted tanks to move up and successfully capture the pass. The advance continued. Dras, Kargil and Leh were liberated and Ladakh cleared of the infiltrators.