TAIPEI (Reuters) – Taiwan’s air force scrambled on Friday to warn away 10 Chinese aircraft that entered its air defence zone, Taiwan’s defence ministry said, the day after the island announced a $9 billion boost to military spending to counter the threat from China.

Chinese-claimed Taiwan complained for more than a decade about China’s repeated air strikes on its democratically-governed island. These attacks were often located in the southwest corner of Taiwan’s air defense zone, near Taiwan-controlled Pratas Island.

According to the Taiwan ministry, 6 J-16 fighters and 2 J-11 fighters were involved in this latest Chinese operation. They also included one reconnaissance and anti-submarine aircraft.

The ministry stated that Taiwan deployed combat aircraft to alert the Chinese planes, and missile systems were used to track them.

According to a ministry map, the Chinese fighters flew near the Pratas while reconnaissance and anti-submarine aircraft flew to the Bashi Channel, which separates Taiwan and the Philippines.

China has not yet commented.

China did not immediately comment on the incident, which occurred one day after Taiwan suggested an increase in defense spending to $8.69 billion for the next five-years. This included additional missiles and warnings of the need to urgently upgrade weapons against a “severe danger” from China.

Taiwan Premier Su Tseng Chang stated earlier that China was a serious threat to the country.

“The Chinese Communists plot against our country constantly,” he stated.

Taiwan’s defense expenditures are based on protecting national sovereignty, national safety, and national security. There must be no relaxation. “We must be prepared so that there is no war,” he said.

China’s government criticized Taiwan Foreign Minister Joseph Wu for his comments made last week that Taiwan was “sea fortress”, preventing China’s expansion in the Pacific.

China’s Taiwan Affairs Office released a statement saying that Wu’s aim was “to deceive public opinions, to rope-in and collide with anti-China Foreign Forces”.