BEIJING (Reuters) - China’s air force has conducted more “island encirclement patrols” near Taiwan, its military said on Tuesday, after a senior Chinese diplomat threatened that China would invade the self-ruled island if any U.S. warships made port visits there.

China considers Taiwan to be a wayward province and has never renounced the use of force to bring it under its control.

Numerous Chinese fighter jets, bombers and surveillance aircraft conducted “routine” and “planned” distant sea patrols on Monday to safeguard national sovereignty and territorial integrity, Air Force spokesman Shen Jinke said on the military branch’s microblog.

H-6K bombers, Su-30 and J-11 fighter jets, and surveillance, alert and refueling aircraft flew over the Miyako Strait in Japan’s south and the Bashi Channel between Taiwan and the Philippines to “test real combat capabilities”, Shen said.

Taiwan Defence Minister Feng Shih-kuan said in a statement they had dispatched aircraft and ships to monitor the activity of the Chinese military and that the drills were not unusual and people should not be alarmed.

China has conducted numerous similar patrols near Taiwan this year, saying such practices have been normalized as it presses ahead with a military modernization program that includes building aircraft carriers and stealth fighters to give it the ability to project power far from its shores.

Beijing regularly calls Taiwan the most sensitive and important issue between it and the United States. Taiwan is well armed, mostly with U.S. weaponry, but has been pressing Washington to sell it more high-tech equipment to better deter China.

In September, the U.S. Congress passed the National Defense Authorization Act for the 2018 fiscal year, which authorizes mutual visits by navy vessels between Taiwan and the United States.

That prompted a senior U.S.-based Chinese diplomat to say last week that China would invade Taiwan the instant any U.S. navy vessel visited Taiwan.

China suspects Taiwan President Tsai Ing-wen, who leads the independence-leaning Democratic Progressive Party, wants to declare the island’s formal independence. Tsai says she wants to maintain peace with China but will defend Taiwan’s security.