The US and its NATO allies have repeatedly engaged in activities in the South China Sea, such as carrying aircraft carrier exercises or deploying submarines to patrol to increase pressure on China.

The aircraft carrier strike group Theodore Roosevelt and Nimitz on 9/2 rehearsed in the South China Sea.

A day earlier, nuclear submarines attacked the Émeraude and a French supply ship patrolled the South China Sea, to "assert that international law was the only rule in force, regardless of which sea area they were.

Hu Bo, director of the Beijing-based East Sea Strategic Situation Advisory, says the US and French operations are an attempt to put more pressure on China.

The Biden administration has said that China will be the center of its foreign policy and Washington will work with partners to develop a competitive strategy with Beijing.

According to Collin Koh, an expert from S Rajaratnam School of International Studies at Singapore's Nanyang Technological University, the US Navy is sending a message that the force can operate "wherever it wants to if the law is national.

Meanwhile, France wants to emphasize its interests in the Indo-Pacific.

Observers say that US allies, including Britain, will carry out more patrols as they want to repel Beijing's militarized activities and actions in the region.

China unilaterally outlined the "cow's tongue line" claim, claiming sovereignty over most of the South China Sea.

"This can be seen as a kind of NATO expansion and they will increase the military pressure on China," said military commentator Song Zhongping, a former coach of the Chinese military.

Zhu Feng, executive director of the South China Sea Collaborative Research Center at Nanjing University, said that adding more naval activities in the region such as those deployed this week could increase the risk.