The drills, which will take place less than 25 kilometers (15.5 miles) off the coast of south China’s Hainan province, come as the US leads concerns over China’s increasing military and economic footprint in a region stretching from the South China Sea to the Pacific Islands.

“Military exercises will be held and entry is prohibited,” the Marine Safety department said in a statement Thursday, closing off a 100-square-kilometer region to maritime traffic for five hours.

China frequently performs such drills in waters near its coastlines, with another exercise near Hainan slated for next week, as well as several more around the country’s eastern coast.

The new maneuvers, however, come as Beijing faces a rising chorus of warnings from the US and Western allies about its naval aspirations, which critics believe are a prelude to a larger push to shift the power balance.