China's military is rehearsing the encirclement of Taiwan during three days of military drills, reports BBC.
The exercises began hours after President Tsai Ing-wen returned from a trip to the United States. Beijing - which views Taiwan as a breakaway province of China - called the operation a "stern warning" to the island's government.
The Taiwanese Defence Ministry said 71 Chinese military planes and nine ships crossed the Taiwan Strait median line.
The line is an unofficial dividing line between Chinese and Taiwanese territory.
One of the ships fired a round from its deck as it sailed near Pingtan island, China's closest point to Taiwan.
Meanwhile, Chinese state media said the military drills would "simultaneously organise patrols and advances around Taiwan island, shaping an all-round encirclement and deterrence posture".
It added that "long-range rocket artillery, naval destroyers, missile boats, air force fighters, bombers, jammers and refuellers" had all been deployed by China's military.
Taiwan considers itself a sovereign state, with its own constitution and leaders.
Although China often holds drills around Taiwan, the "encirclement" is being seen as a response to Taiwan's President Tsai meeting US House Speaker Kevin McCarthy on Wednesday.
President Tsai said on Saturday that her government would continue working with the US and other democracies as the island faces "continued authoritarian expansionism" from China.
She made the comments in a meeting with a US congressional delegation in Taipei led by House foreign affairs committee chairman Michael McCaul.
Bd-pratidin English/Golam Rosul