China plans to close airspace north of Taiwan next week, the self-ruled island’s defense ministry said on Wednesday, which could disrupt flights in the region amid rounds of intense military drills by Beijing.

When asked about an earlier Reuters report on the airspace’s closing, Yan Yu-hsien, deputy chief of the general staff for intelligence from Taiwan’s defense ministry, said the “no-fly zone” would fall within the country’s air defense identification zone (ADIZ), about 85 nautical miles north of its shores.

“We all know that there are many international flights to Japan and the United States from Taiwan’s north,” Yan said, adding that the ministry was aware of the development and was closely monitoring it.

An ADIZ is a section of international airspace countries can arbitrarily define as theirs to monitor.

Chinese foreign ministry spokesman Wang Wenbin said he was unaware of the situation.

Japan said on Wednesday China had notified it about a no-fly zone near Taiwan from April 16-18, saying it related to aerospace activities.

The closings will coincide with a meeting of Group of Seven (G7) foreign ministers scheduled to take place in Japan the same dates.

One senior government official with direct knowledge of the matter said the flight ban would affect 60 percent-70 percent of flights between Northeast Asia and Southeast Asia, as well as flights between Taiwan and South Korea, Japan and North America. The official declined to be named because of the sensitivity of the matter.

When China imposed such restrictions during military drills last August, there were significant disruptions to flights in the region, with some aircraft required to carry extra fuel, according to OPSGROUP, an aviation industry cooperative that advises on flight risks.

Japanese authorities said that there were no major flight cancelations to or from Japan during those drills.

Stormy seas

Earlier on Wednesday, China said President Tsai Ing-wen was pushing Taiwan into “stormy seas” after meeting with US House Speaker Kevin McCarthy in California.

Tsai said the overseas trip, which included the meeting with McCarthy in the US and stops in Guatemala and Belize, showed the world Taiwan’s determination to defend freedom and democracy.

The trip infuriated Beijing, prompting days of military drills designed to show it could forcefully retake control of the self-ruled island, which China claims as its own.

China views Tsai as a separatist and has rebuffed repeated calls from her for talks. Tsai says she wants peace but that her government will defend Taiwan if it is attacked.

“Tsai Ing-wen brought danger to Taiwan. Tsai Ing-wen almost completely sided the United States, pushing Taiwan into stormy seas,” China’s Taiwan Affairs Office (TAO) spokesperson Zhu Fenglian said on Wednesday.

Zhu said the drills around Taiwan were “a serious warning against the collusion and provocation of Taiwan independence separatist forces and external forces.”

Tsai, who returned to Taiwan a day before the drills began, said the trip had been a success in winning support against an aggressor that was threatening the island’s freedom.

“Through this trip we again sent a message to the international community that Taiwan is determined to safeguard freedom and democracy which won acknowledgment and support from our democratic partners,” Tsai said as she met Canadian lawmakers at her office in Taipei.

“Faced with continued authoritarian expansionism it is even more critical for democracies to actively unite,” she added.

“Canada is a very important democratic partner. We are willing to do our utmost to jointly safeguard the values of freedom and democracy with Canada and many more like-minded international partners.”

Despite the tensions with China, Tsai looked relaxed as she greeted the 10 Canadian legislators, even cracking a joke.

Beijing has continued military activities around Taiwan, despite announcing the three days of drills had ended as scheduled on Monday.

The ministry said earlier on Wednesday that in the previous 24 hours it had detected 35 Chinese military aircraft and eight navy vessels around Taiwan.

Of those aircraft, 14 had crossed the median line of the Taiwan Strait, according to a ministry-provided map; the line normally serves as an unofficial barrier between the two sides.

The aircraft crossing the median line included five Su-30 fighters at its northern end, with the other planes crossing at points in the center and south.

Although Chinese fighters previously only occasionally crossed the median line, the country’s air force has done so regularly since staging war games near Taiwan in August, after a visit to Taipei of then-US House Speaker Nancy Pelosi.

China says it does not recognize the existence of the line.

Taiwan’s government strongly rejects China’s sovereignty claims and says only Taiwan’s people can decide their future.