TAIPEI (Taiwan News) — The Ministry of National Defense said it had tracked 13 aircraft and four ships from China’s military around the country by 5 p.m. Wednesday (Aug. 24).

Of the 13 People’s Liberation Army Air Force (PLAAF) warplanes, two crossed the median line over the Taiwan Strait near its northern end, the military said. The two planes were both Sukhoi Su-30 fighter jets.

The ministry said it sent combat patrol aircraft, Navy ships, and land-based air defense missile systems to monitor and respond to Chinese activities, while also issuing radio warnings.

The incursions came as Kuomintang (KMT) Vice Chairman Andrew Hsia (夏立言) was preparing for a dinner in the Chinese city of Kunshan on Wednesday with Zhang Zhijun (張志軍), the head of China’s Association for Relations Across the Taiwan Straits (ARATS). Hsia’s trip was widely criticized in Taiwan for its timing during Chinese military maneuvers, including the firing of missiles.