BEIJING: The Chinese Ministry of Defense has announced that China and Russia will launch a joint military drill in the South China Sea in September, a move observers say shows the two countries have formed a "semi-alliance" in the face of an increasingly assertive US.

"This is a routine drill between two military forces aimed at strengthening the developing China-Russia strategic cooperative partnership," said Yang Yujun, spokesperson for the Ministry of National Defense during a regular monthly press conference in Beijing.

Even though Yang said the exercise is not directed against third parties, experts consider that the choice of location and the timing show the drill is aimed specifically at countering the increasing US military presence in the Asia-Pacific.

Shi Yinhong, director of the Center for American Studies at the Renmin University of China, told the Global Times that "due to the great pressure Russia receives from the West in Europe, Moscow is becoming more motivated to having deeper strategic cooperation withBeijing at this moment. The drill is an obvious example in the military area."