The Taipei Defense Ministry said at least 19 Chinese fighter jets and bombers, including an anti-submarine aircraft, had crossed the Taiwan Strait.

A similar incident had taken place on Friday. Officials from Japan and the United States are visiting Taipei these days, including US Undersecretary of State Keith Krach, the highest-ranking official in Washington who has arrived in Taiwan in recent decades.

Beijing does not recognize Taiwan’s independence and considers the island part of Chinese territory. Chinese state media have threatened that Taiwanese President Tsai Ing-wen will be “wiped off the face of the earth.” An editorial in the Global Times warns that China “is determined to take any necessary measures, including military options,” to prevent closer ties between Taiwan and the United States.

Tsai, Krach, and former Japanese Prime Minister Yoshiro Mori on Saturday paid tribute to former Taiwanese President Lee Teng-hui, who died on July 30, for his role in democratizing Taiwan during his 12-year term. They offered their condolences as close friends of Lee, former Japanese Prime Minister Shinzo Abe and Tibetan leader Dalai Lama.

Chinese airstrikes have given U.S. and Japanese officials in Taiwan the opportunity to feel directly intimidated by China, said Taipei government-funded National Defense and Security Research Institute analyst Su Tzu-yun.