In light of escalating military tensions across the Taiwan Strait, Taiwan’s defence minister, Chiu Kuo-cheng, issued a warning on Monday that the island must be on high alert for a “sudden entry” by the Chinese military into areas near to its territory this year.

In recent years, China has increased its military operations in the vicinity of Taiwan, including nearly daily air force intrusions within the island’s air defense identification zone.

However, Taiwan has not reported any incident of Chinese forces entering its contiguous zone, which is 24 nautical miles (44.4 km) from its coast. But it has shot down a civilian drone that entered its airspace near an islet off the Chinese coast last year.

Answering questions from lawmakers in parliament, Chiu said the Chinese People’s Liberation Army (PLA) might find excuses to enter areas close to Taiwan’s territorial air and sea space as the island steps up its military exchanges with the United States, to Beijing’s ire.

He said the PLA might make a “sudden entry” into Taiwan’s contiguous zone and get close to its territorial space, which the island defines as 12 nautical miles from its coast.

“(I) specifically make these comments this year, meaning they are making such preparations,” Chiu said. “Looking forward, they would use force if they really have to.”

In response, Chinese foreign ministry spokesperson Mao Ning said at a daily briefing that Beijing “will take firm measures to defend its sovereignty and territorial integrity.”

Taiwan has vowed to exercise its right to self-defence and counter-attack if Chinese armed forces entered its territory.

China last year staged unprecedented military exercises around Taiwan in reaction to a visit to the island by then-U.S. House Speaker Nancy Pelosi.

Chiu said China was looking to “make trouble under a certain pretext”, adding that might include visits to the island made by senior foreign government officials or Taiwan’s frequent military contacts with other countries.

Asked by a lawmaker if the United States was planning to store some of its military equipment in Taiwan, Chiu said such discussions were ongoing but declined to elaborate.

The United States is Taiwan’s most important international arms supplier and increasing U.S. support for the democratic island has added to tension in already strained U.S.-Sino relations.

Chiu said the PLA sends about 10 planes or ships to areas near Taiwan a day. Some cross the median line of the Taiwan Strait, which has traditionally served as an unofficial buffer, on an almost daily basis, he said.

Chiu said since China has abandoned a tacit agreement on military movements in the Strait, Taiwan has made preparations to “fire the first shot” if Chinese entities, including drones or balloons, enter its territorial space.

China claims self-governed Taiwan as its own and has not renounced the use of force to bring it under Chinese control, if needed. Taiwan strongly rejects China’s sovereignty claims and says only its people can decide their future.