Taiwan scrambled jets on Thursday to warn away 22 Chinese aircraft in its air defense zone, the Taiwanese defense ministry said.

All 22 Chinese aircraft crossed the Taiwan Strait median line, a ministry statement said.

China also fired live missiles near Taiwan on Thursday in its biggest drills in the Strait, a day after US House of Representatives Speaker Nancy Pelosi made a solidarity trip to the self-ruled island.

China’s military confirmed multiple firings of conventional missiles in waters off Taiwan as part of planned exercises in six zones set to run until noon on Sunday. It activated more than 100 planes, including fighter jets and bombers, and over 10 warships, state broadcaster CCTV said.

Responding to the Chinese drills, President Tsai Ing-wen said Taiwan would not provoke conflicts but would firmly defend its sovereignty and national security.

“Taiwan will never be knocked down by challenges,” Tsai said in a recorded video message to the people of Taiwan.

“We are calm and not impetuous, we are rational and not provocative, but we will also be firm and not shirk.”

To avoid escalating tensions with Beijing any further, the United States postponed a routine test launch of an Air Force Minuteman III intercontinental ballistic missile, the Wall Street Journal reported on Thursday, citing US officials. One official said the delay might last 10 days, the report said.

Chinese Foreign Minister Wang Yi called Pelosi’s visit to Taiwan a “manic, irresponsible and highly irrational” act, state broadcaster CCTV reported.

Wang, speaking at a meeting of Southeast Asian foreign ministers in Cambodia, said China had tried to avert crisis by diplomatic means but would never let its core interests be hurt.