Taiwan鈥檚 Defense Ministry said Saturday it was monitoring 鈥渨aves of test-firing鈥� by China鈥檚 missile unit in a region more than 1,600 kilometers (1,000 miles) from the self-ruled island and that its air force stepped up its alertness.

China views the democratic island as a breakaway province that should be reunified with the mainland.

According to Taiwan鈥檚 military news agency, the ministry had detected 鈥渕ultiple waves of test-firing operations鈥� by China鈥檚 Rocket Force in Inner Mongolia on Saturday. It did not give details on the tests taken by the force, which takes charge of China鈥檚 arsenal of missiles.

It is not immediately clear whether the tests were related to China鈥檚 harassment of Taiwan. In recent years, China has ramped up its military activities around the island, which is ruled by the Democratic Progressive Party.

In May, Taiwan鈥檚 newly elected President Lai Ching-te said in his inauguration speech that he wants peace with China and urged it to stop its military threats and intimidation of the island.

China鈥檚 military has displayed a strong show of force toward Taiwan since Wednesday, when the U.S. new top envoy to Taipei promised that Washington would help the island defend itself.

Taiwan鈥檚 Defense Ministry said Thursday it had detected 66 warplanes around the island and that dozens flew across the median line in the Taiwan Strait, the de facto boundary between the two sides.

On Saturday, 30 warplanes also were detected around Taiwan over a 24-hour period with 20 crossing the median line.

The U.S., like most countries, does not recognize Taiwan. But it鈥檚 the island鈥檚 main partner and is bound by U.S. laws to provide it with the means to defend itself. Less than a month ago, the U.S. State Department approved the sale to Taiwan of missiles and drones for an estimated $360 million.

The Associated Press