BEIJING (Reuters) - The United States must respect China’s concerns on Taiwan to avoid causing disturbances in Sino-U.S. ties, Chinese Foreign Minister Wang Yi told visiting U.S. Secretary of State Rex Tillerson on Saturday. China considers democratic Taiwan to be a wayward province and has never renounced the use of force to bring the island under its control. The United States has no formal ties with Taiwan but is bound by law to help it defend itself and is the island’s main source of arms. China regularly calls Taiwan the most sensitive and important issue between it and the United States, and has been upset by U.S. moves to expand military exchanges with Taiwan and continued U.S. arms sales to the island. Wang explained China’s position on the Taiwan issue and “demanded the U.S. side earnestly respect China’s concerns, appropriately handle the relevant issue and avoid bringing disturbances to China-U.S. relations”, China’s Foreign Ministry said. It did not elaborate. Beijing’s relationship with Taiwan has been frosty since President Tsai Ing-wen won election on the island by a landslide last year. China suspects that Tsai, who leads the pro-independence Democratic Progressive Party, wants to declare the island’s formal independence, a red line for Beijing. Tsai says she wants to maintain peace with China. In recent months the Chinese air force has conducted a series of drills around Taiwan, which have included bombers and advanced fighter jets, alarming Taipei. China has called the exercises routine and pledged to continue with them.  