
Extract the answer to the question from the following context.
Question: Why did soldiers land on the island of Mindoro?
Context: On 15 December 1944 landings against minimal resistance were made on the southern beaches of the island of Mindoro, a key location in the planned Lingayen Gulf operations, in support of major landings scheduled on Luzon. On 9 January 1945, on the south shore of Lingayen Gulf on the western coast of Luzon, General Krueger's Sixth Army landed his first units. Almost 175,000 men followed across the twenty-mile (32 km) beachhead within a few days. With heavy air support, Army units pushed inland, taking Clark Field, 40 miles (64 km) northwest of Manila, in the last week of January.

a key location in the planned Lingayen Gulf operations
