China’s military activity is heating up as Taiwan officials reported on Monday, Sept. 18. According to the reports, China has been sending groups of fighter jets and warships into areas around Taiwan.

The Taiwan Ministry of National Defense reported that more than a hundred Chinese aircrafts and nine Chinese naval ships were operating near the island between Sunday, Sept. 17, and Monday, Sept. 18.

The reports state that around 40 aircraft crossed into Taiwan’s side of the Taiwan Strait. Authorities and analysts in the U.S. and Taiwan say these latest actions by Beijing are more about training than sending a message, The Wall Street Journal reported.

Officials worry that China is working on how to most effectively encircle Taiwan and prevent the U.S. from coming to the island’s aid in response to an invasion. 

This comes as the U.S. sends two drone-ship prototypes to Japan for their first deployments in the western Pacific. These drones have surveillance and attack capabilities that are being tested by the Navy. Experts believe these drones could prove useful in any future conflicts with china.

The Taiwan Ministry of National Defense said in its release that Taiwan leaders are responding to China’s actions calmly as they call on officials in Beijing to take responsibility and put an immediate stop to “such destructive unilateral actions.”