The exercises follow a rise in Chinese rhetoric against Taiwan President Lai Ching-te, who China called a "parasite" on Tuesday, and come on the heels of US Defence Secretary Pete Hegseth's Asia visit, during which he repeatedly criticised Beijing.
China, which views democratically governed Taiwan as its own territory, has repeatedly denounced Lai as a "separatist". Lai, who won election and took office last year, rejects Beijing's sovereignty claims and says only Taiwan's people can decide their future.
China's Eastern Theatre Command said the drills were taking place in the middle and southern areas of the Taiwan Strait. Some of Taiwan's outlying islands are just a few kilometres from China.
"The exercises focus on subjects of identification and verification, warning and expulsion, and interception and detention so as to test the troops' capabilities of area regulation and control, joint blockade and control, and precision strikes on key targets," it said in a statement.
A senior Taiwan security official told Reuters there were more than 10 Chinese warships in Taiwan's "response zone" on Wednesday morning, and that China's coast guard was participating with "harassment" drills.
China had not formally named Tuesday's drills. China called two rounds of major war games last year around the island Joint Sword-2024A and Joint Sword-2024B.
The United States, Taiwan's most important international backer and main arms supplier despite the lack of formal diplomatic ties, condemned the exercises.
"Once again, China's aggressive military activities and rhetoric toward Taiwan only serve to exacerbate tensions and put the region's security and the world's prosperity at risk," the US State Department said in a statement.
Japan and the European Union also expressed concern.
"The EU has a direct interest in the preservation of the status quo in the Taiwan Strait. We oppose any unilateral actions that change the status quo by force or coercion," an EU spokesperson said.
