(Bloomberg) -- China sent the biggest number of warplanes close to Taiwan since October on Sunday after a U.S. lawmaker defied a Chinese demand that she abandon a trip to the island.

Twenty-seven Chinese aircraft, including 8 J-16 fighter jets, entered Taiwan’s southwest Air Defense Identification Zone, according to a statement from the Ministry of National Defense. The air force issued radio warnings and deployed air defense missile systems as it monitored the planes.

It’s the largest deployment of Chinese warplanes since a record 52 aircraft were detected close to Taiwan in early October. China has ramped up military, diplomatic and economic pressure on Taiwan’s ruling Democratic Progressive Party, which asserts the island is a de facto sovereign nation awaiting wider international recognition.

Elissa Slotkin, a Democrat from Michigan, wrote on Twitter after landing in Taiwan Thursday that her office received a “blunt message” from the Chinese embassy to call off the trip. The trip also includes Japan and South Korea.

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