The move by China follows a meeting in California between Taiwan President Tsai Ing-wen and US House Speaker Kevin McCarthy.
China on Saturday launched three days of military drills in the Taiwan Strait.
The People's Liberation Army's Eastern Theatre Command said "United Sharp Sword" would run April 8 to 10 for "combat preparedness".
In a PLA statement, Eastern Theatre spokesman Senior Colonel Shi Yi, said "United Sharp Sword" would involve police patrol drills in the Taiwan Strait, "to the north and south of Taiwan, and in the sea and airspace to the east of Taiwan".
The exact location of the exercises was not specified.
Taiwan's defense ministry said Saturday it had detected three warships and 13 Chinese aircraft around the island in the past 24 hours.
The Ministry of National Defence said "4 of the detected aircraft had crossed the median line of the Taiwan Strait and entered Taiwan's southeast ADIZ" in a morning report.
Saturday's move by China follows a meeting in California between Taiwan President Tsai Ing-wen and US House Speaker Kevin McCarthy.
China views self-ruled Taiwan as part of its territory and has vowed to one day seize it, by force if necessary.
Last August, China deployed warships, missiles, and fighter jets around Taiwan in its largest show of force in years, following a trip to the island by McCarthy's predecessor Nancy Pelosi.
There were no initial signs of heightened military activity on Pingtan, a southwestern Chinese island known as the closest point on the mainland to Taiwan.
Tour guides on Saturday morning herded groups of day-trippers along the sun-drenched shore, while other visitors gazed out at the choppy waters of the strait.
AFP journalists on Friday saw a military tugboat and several army helicopters transiting through the seas off Pingtan, but it was unclear if they signaled enhanced activities.
On Friday, Beijing sent warships and aircraft near Taiwan for a second day and said the island remains an "inseparable part" of its territory.
Tsai returned to Taiwan on Friday after visiting the island's dwindling band of official diplomatic allies in Latin America, with two US stopovers that included meetings with McCarthy and other lawmakers.
"We let the international community see that Taiwan is more united when facing pressure and threats," she told reporters, describing her trip as a success, adding "we will never yield to suppression".
Hours before meeting with McCarthy in California on Wednesday, China sent its Shandong aircraft carrier through Taiwan's southeastern waters on its way to the western Pacific.
Beijing said earlier Friday that "Taiwan is an inseparable part of China", after repeatedly warning against the Tsai-McCarthy meeting.
"China's sovereignty and territorial integrity will never be divided," foreign ministry spokeswoman Mao Ning said at a regular press briefing.
"The future of Taiwan lies in reunification with the motherland."
Chinese President Xi Jinping has just hosted French counterpart Emmanuel Macron and European Commission chief Ursula von der Leyen as the EU attempts to repair relations with Beijing.
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