Chinese military aircraft flew through a strategic waterway between Okinawa’s main island and the island of Miyakojima a record 36 times in fiscal 2017, the Japanese Defense Ministry has announced, as China seeks to extend its reach further into the Western Pacific with what it calls “regular” exercises.

The number of flights over the strategic waterway between Okinawa Island and Miyakojima hit a record high of 36 in fiscal 2017, which ended in March, the ministry said Friday.

But although China has been bolstering its operations in the area, the ministry noted a sharp fall in the number of scrambles against Chinese aircraft by Air Self-Defense Force fighter jets in response. That figure fell from a total of 851 in fiscal 2016 to 500 in 2017.

The ministry said that notable Chinese military activity near Japanese territory included the first documentation of a flight by Chinese fighters over the Tsushima Strait, which runs between Kyushu and the Korean Peninsula, in December.

Scrambles against Chinese aircraft made up about 55 percent of the total 904 scrambles, according to ministry data. The number of scrambles against Russian aircraft rose by 89 to 390, or 43 percent of the total.

The Chinese Air Force last conducted exercises over the Miyako Strait late last month, labeling the drills “rehearsals for future wars.”

China is in the midst of a military modernization program heavily promoted by President Xi Jinping, who has overseen a shift in focus toward creating a more potent fighting force, including projects such as building a second aircraft carrier, integrating stealth fighters into its air force and fielding an array of advanced missiles that can strike air and sea targets from long distances.

While Beijing insists that these exercises are in line with international law and practice, and that its modernization program is not directed at any particular country, its moves in the disputed South China Sea and near Japanese islands has prompted concern.