Vietnam has concentrated its attention on the South China Sea's petroleum and natural gas resources. They occupied those reefs on the west side of the Spratly Islands which they felt to be strategically important to them, and sought to collaborate with leading Western oil companies to speed up the development of the oil reserve in the area. Vietnam has taken a very firm stance over sovereignty of the Spratly Islands, which has led to two military conflicts with China. Most of the reefs in the Spratly Islands have been occupied by Vietnam, which is militarily stronger in the region than any other country. The Vietnamese government established a military command post on Spratly Island, which has helicopter landing pads and runways. It is an important point on the South China Sea navigation route, as well as constituting an important foothold for Vietnam in the development of the South China Sea's petroleum and gas resources.