Jan. 24 (UPI) -- China's air force has sent more than three dozen warplanes through Taiwan's air defense zone in its largest incursion since October, officials in Taipei said, causing the island to scramble fighter jets in response.
The Taiwanese defense ministry said that China flew 39 aircraft, including 24 J-16 and 10 J-10 fighter jets as well as one H-6 bomber, through the southwestern part of its air defense identification zone, or ADIZ, on Sunday night.
Taiwan issued radio warnings, activated missile defense systems and scrambled its own fighter aircraft in response, the ministry said. The Chinese flights passed near the Taiwan-administered Pratas Islands, according to a map from the ministry.
While China routinely flies aircraft into Taiwan's air defense zone, Sunday's mission was the largest since the beginning of October, when Beijing sent nearly 150 planes over a four-day period around its National Day holiday.
The incursion came a day after the U.S. Navy and Japan's Maritime Self-Defense Force concluded a multi-day joint exercise in the Philippine Sea, which includes waters to the east of Taiwan.
China considers Taiwan a breakaway province and has vowed to retake it by force if necessary. Over the past several months, Beijing has ratcheted up military provocations with flights and gestures such as beach landing drills in a nearby province.
In a November defense ministry report, Taiwan said that China was using "gray zone" warfare to weaken its defense capabilities and wear down public morale.
"[China's] intimidating behavior does not only consume our combat power and shake our faith and morale but also attempts to alter or challenge the status quo in the Taiwan Strait to ultimately achieve its goal of 'seizing Taiwan without a fight,'" the ministry's report said.
Earlier this month, a Taiwanese F-16V jet crashed into the sea during a routine drill. Last year, another F-16 went down after leaving Hualien air base and two F-5E fighters crashed into the sea after they collided in mid-air.
The U.S. Seventh Fleet tweeted on Sunday that joint exercises with Japan reaffirmed a "commitment to the free and open Indo-Pacific." The flotilla included a pair of U.S. Navy aircraft carriers, the USS Carl Vinson and the USS Abraham Lincoln, as well as a Japanese helicopter destroyer.
The Navy on Monday said the show of force in the Philippine Sea included enhanced maritime communications and anti-submarine warfare operations as well as combat readiness and a slew of other objectives.
"We are committed to ensuring the lawful use of the sea and free flow of commerce while deterring those who challenge the shared vision of a free and open Indo-Pacific now and into the long-term future," Read Adm. Dan Martin said in a statement.
The Navy said the exercise is part of its routine presence in the region, and it occurred as the Biden administration seeks to increase its influence in the Indo-Pacific region to counter China's aggression.
Beijing not only accuses the United States of trespassing when entering the East China Sea but lays claims to much of the South China Sea, where Vietnam and Taiwan also claim sovereignty over the 130 small coral islets of the Paracel Islands.
President Joe Biden on Friday spoke with Japanese Prime Minister Kishida Fumio in a virtual meeting where to two shared opinions on advancing their "shared vision of a free and open Indo-Pacific region."
"The two leaders resolved to push back against the People's Republic of China attempts to change the statue quo in the East China Sea; underscored the importance of peace and stability across the Taiwan Strait and the peaceful resolution of cross-Strait issues," a White House readout of the meeting said.
On Thursday, the Seventh Fleet also sent a destroyer on a freedom of navigation operation near the Paracel Islands.
China's military called the operation "illegal" and warned of "serious consequences."