The Taiwanese armed forces have conducted anti-aircraft drills involving US-made Patriot missile defense systems, the island’s defense ministry said on Tuesday.

The exercise was carried out from 5 a.m. to 7 a.m. local time (21:00-23:00 GMT, March 25), the ministry said in a statement. The goal of the drills was to improve the all-round combat capability of military defense operations.

The Taiwanese air force will continue to step up the intensity of drills, the statement said.

The statement quoted alleged “incursions by Chinese Communist Party aircraft and ships into the sea and airspace around Taiwan” and added that “the air force will continue to increase the intensity of drills” in order to respond to these alleged threats.

Taiwan has been governed independently of mainland China since 1949. Beijing views the island as its province, while Taiwan — a territory with its own elected government — maintains that it is an autonomous country but stops short of declaring independence. Beijing opposes any official contacts of foreign states with Taipei and considers Chinese sovereignty over the island indisputable.