BEIJING — China intends to project naval power in the open ocean in coming years, and not just defend the country’s coastal waters, according to a strategy paper released on Tuesday.

The paper, the first policy document issued by the Chinese military in two years, comes at a time of growing Chinese assertiveness in the South China Sea. China’s efforts to enforce its disputed claims to vast stretches of the sea by building up artificial islands and structures on reefs and outcroppings have drawn the Philippines and its ally the United States into a test of wills in the region.

The dispute between Beijing and Washington escalated last week when an American military surveillance plane flew near Fiery Cross Reef, a contested atoll in the Spratly Islands that has been the site of frenetic dredging work in recent months. Chinese forces repeatedly ordered the American plane to leave the area, and a Foreign Ministry spokesman later called the flight “irresponsible and dangerous.”

The Pentagon said earlier this month that it was weighing whether to send warships and aircraft into what it says are international waters, but China says are within its zone of control.