The Chinese defence ministry announced Thursday that in September it will hold "routine" military drills with Russia in the South China Sea.
Many international observers are likely to see the move as an escalation of tensions in the disputed region, but the ministry argued it was about greater Russian-China cooperation.
"This is a routine exercise between the two armed forces, aimed at strengthening the developing China-Russia strategic cooperative partnership," ministry spokesman Yang Yujun said. "The exercise is not directed against third parties.
"These drills deepen mutual trust and expand cooperation, raise the ability to jointly deal with security threats, and benefit the maintenance of regional and global peace and stability."
China is still reeling from losing an international arbitration case against the Philippines over the region (See: Tribunal rules against Beijing in South China Sea dispute). China does not accept the legitimacy of that ruling, calling it "null and void." On Wednesday, the United States said that it would continue freedom of navigation operations in the area, according to a senior navy officer. The US has officially remained neutral in the dispute between the Philippines and China.
The US "does not take a position on the side of one claimant or another claimant", secretary of State John Kerry said Wednesday.
"What we are pushing for is absolute support for rule of law, for the legal process, and for diplomacy to work out the differences that people have," Kerry said.
But the Obama administration has long been under pressure from some to be more hawkish, and China has seen the US as having an agenda in the region, despite assurances like Kerry's.
"We continue to restrict our navy from operating within a 12 nautical mile zone of China's reclaimed islands, a dangerous mistake that grants de facto recognition of China's man-made sovereignty claims," veteran Republican Senator John McCain Arizona, seen as an expert on defence affairs, complained in 2015.