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

Spokesman Wu Qian told reporters at a Thursday briefing that China had already been formally invited to take part in the Pacific Rim drills.

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 exercises 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.