Frequent and increased Chinese military drills pose an “enormous threat” to Taiwan’s security, Taipei warned on Tuesday in an annual defense review. Beijing has stepped up drills around the island since Taiwanese President Tsai Ing-wen took office last year, AFP said. Local media estimate Chinese warplanes have conducted at least 20 drills around Taiwan this year, compared to just eight in 2016. The latest known drill took place last week when several Chinese planes, including jet fighters, reportedly passed through the Bashi Channel south of Taiwan to the Pacific and back.