China's Defense Ministry said Thursday it is consulting with the U.S. over again participating in large-scale multinational military exercises being held this summer.

Spokesman Wu Qian told reporters at a monthly briefing that China had already been formally invited to take part in the Pacific Rim drills hosted by the U.S. Navy.

"We are now discussing details with the U.S. side on arrangements for China's participation," Wu said.

China has joined in the exercises twice before, despite frequently complaining about U.S. Navy activity in the South China Sea, which China claims as its territory.

The U.S. for its part routinely questions the objectives of China's massive military buildup and has criticized Beijing for carrying out extensive land reclamation work on many of the islands and reefs it claims, equipping some with air strips and military installations.

On Saturday, China accused the U.S. of trespassing in its territorial waters in the South China Sea after the guided missile destroyer USS Hopper sailed within 12 nautical miles (22 kilometers) of Scarborough Shoal on Wednesday evening without China's permission.

China seized the tiny, uninhabited reef from the Philippines in 2012. Known in Chinese as Huangyan Island, it lies about 600 kilometers (370 miles) southeast of China.

The South China Sea has crucial shipping lanes, rich fishing grounds and potential oil, gas and other mineral deposits.

The U.S.-hosted naval drills known as RIMPAC are held every other year and in 2016 included 45 ships, 200 aircraft and more than 25,000 people from 26 nations.

China brought several vessels, including a hospital ship. U.S. law limits the scope of U.S. military drills with China to areas such as search and rescue and humanitarian and disaster relief.