The number of aircraft sent into the ADIZ is one of the largest since early October, when the People’s Liberation Army (PLA) sent around 150 warplanes into the air defense zone in separate maneuvers over five days.

The ministry said it issued radio warnings and monitored the aircraft on Saturday using air defense systems. The jets entered the ADIZ off Taiwan’s southwestern coast, following a path similar to previous incursions.

What is Taiwan’s ADIZ?

The ADIZ extends hundreds of kilometers from Taiwan’s coast and even includes parts of mainland China. It is much larger than Taiwan’s sovereign air space, which only extends 12 nautical miles from the coast.

The ADIZ is airspace designated for national security purposes but is not delineated in international treaties. Taiwanese authorities reserve the right to order aircraft entering the ADIZ to identify themselves and their purpose.

Although China has flown regular incursions with smaller numbers of aircraft into the ADIZ over the past several weeks, the warplanes have not entered Taiwan’s sovereign airspace.

EU delegates visit Taiwan

The Chinese flights into the ADIZ on Saturday came a day after a European Parliament delegation wrapped up a three-day visit to Taipei.

The seven lawmakers on the parliament’s committee on foreign interference in democratic processes visited last week, following up on a resolution last month calling for the body to “intensify EU-Taiwan political relations.”

EU parliamentarians said the visit was not aimed at provoking China, which sees self-governing Taiwan as part of its territory and usually considers any attempt at building bilateral ties between Western nations and the government in Taipei as a provocation.