"Since 0900 (UTC+8) today (Aug. 19), the R.O.C. Armed Forces detected 42 PLA aircraft," the island's ministry of defence said in a statement.

Twenty-six of the warplanes involved crossed the median line of the Taiwan Strait, the ministry said.

Eight vessels also participated in the drills, which Chinese state media said were intended to simulate "real combat conditions".

"The National Army is... monitoring and using reconnaissance methods to strictly control (the situation)," Taiwan's defence ministry said, adding that it had dispatched aircraft and ships.

China announced earlier Saturday that it had "launched joint air and sea patrols and military exercises of the navy and air force around the island of Taiwan", according to state media outlet Xinhua.

The drills were conducted after Taiwan's Vice President William Lai made stopovers in the United States -- in New York en route to Paraguay and in San Francisco when returning to Taipei.

China has ramped up pressure against Taiwan in the past year, sending near-daily warplanes incursions and vessels around the island.

It often lashes out at any diplomatic action that appears to treat Taiwan as a sovereign nation.

In April, Beijing conducted three days of military exercises simulating a blockade of the island in response to Republican House Speaker Kevin McCarthy and Taiwan's leader Tsai Ing-wen meeting in California.