Taiwan said China’s military drills on Saturday appeared to be simulating an attack on its main island, as Chinese warplanes and warships crossed the strait’s median line in a continued show of force.

The Taiwanese army responded by sending air patrols and naval ships, deploying land-base missile systems and issuing radio warnings, the Defense Ministry said in a statement.

The self-ruled island scrambled jets to warn away 20 Chinese aircraft, including 14 that crossed the Taiwan Strait median line, the ministry said. It also detected 14 Chinese military ships conducting activities around the Taiwan Strait.