BEIJING - China said Taiwan should not be so suspicious of its intentions on Wednesday after Taipei protested against Beijing’s decision to open new domestic commercial air routes over the Taiwan Strait which separates the two diplomatic rivals.

The Taiwan Affairs Office of China’s State Council said Taiwan must be ‘more understanding and less suspicious’ of the four routes, state media said. Taiwan said on Tuesday it would step up air surveillance patrols in the Taiwan Strait in response ‘if necessary’. China deems Taiwan a renegade province and hasn’t ruled out the use of force to take it back, particularly if the island makes a move toward independence. Beijing’s ‘one China‘ policy holds that there is only one China and that Taiwan is part of it.

Taiwan’s Ministry of Transportation  said that Beijing’s decision to open the new routes was ‘unilateral’ and ‘not acceptable’ and could increase flight safety risks.

, particularly around Taiwan’s outlying islands of Kinmen and Matsu. The routes are between eastern Shanghai and the southern Pearl River Delta. The two sides had been discussing a new north-south air route on the west side of the median line dividing the Taiwan Strait, but talks had not yet finished, the ministry said. While Taiwan and China have signed a series of landmark trade and economic agreements since 2008, political and military suspicions still run deep, especially in democratic Taiwan where many fear China’s true intentions.