The Pearl Harbor destroyer USS Preble and its crew of more than 300 have angered China twice this week with a transit of the Taiwan Strait on Wednesday and a South China Sea passage Monday close to Scarborough Shoal — a feature controlled by China but also claimed by Taiwan and the Philippines.

Preble’s “freedom of navigation” operation Monday was its third in the South China Sea since February.

Cmdr. Clay Doss, a spokesman for the Navy’s Seventh Fleet in Japan, said Preble and the oiler USNS Walter S. Diehl “conducted a routine Taiwan Strait Transit May 22-23 (local time) in accordance with international law. The ships’ transit through the Taiwan Strait demonstrates the U.S. commitment to a free and open Indo-Pacific. The U.S. Navy will continue to fly, sail and operate anywhere international law allows.”

China was not happy. Again.

China “has been closely monitoring from start to end the passage by the U.S. warships through the Taiwan Strait,” Foreign Ministry Spokesperson Lu Kang said during a regularly scheduled press briefing. “We have expressed our concern to the U.S. side.”

The Taiwan issue “is the most important and sensitive one in China-U.S. relations,” he said. He urged the United States to “prudently and properly handle Taiwan-related issues so as to avoid negative impacts on China-U.S. relations and the peace and stability across the Taiwan Strait.”

Congressional support for Taiwan as a democracy (China considers it to be a renegade province), has increased in recent years.

“Congress has been consistent for four decades: Taiwan and its 23 million inhabitants are our democratic partners to which we have a solemn commitment,” the House Foreign Affairs Committee tweeted on May 13. “It is Beijing’s increasing pressure on Taiwan and attempts to undermine Taiwan’s democracy that alters the status quo.”

In Monday’s operation in the South China Sea, Preble sailed within 12 nautical miles of Scarborough Shoal “in order to challenge excessive maritime claims and preserve access to the waterways as governed by international law,” the Seventh Fleet’s Doss said at the time.

“U.S. Forces operate in the Indo-Pacific region on a daily basis, including in the South China Sea,” Doss said. “All operations are designed in accordance with international law and demonstrate that the United States will fly, sail and operate wherever international law allows.”

China’s Foreign Ministry said the Preble “trespassed into the adjacent waters” of the shoal it calls Huangyan Dao without permission from the Chinese government.

“The Chinese Navy identified and verified the U.S. warship according to law, and warned it off,” Lu, the ministry spokesman, said. “I have to stress again that the trespass of U.S. warship is a violation of China’s sovereignty.”

The United States does not recognize the shoal as China’s territory. An estimated $3.4 trillion worth of international shipping passes through the South China Sea each year, and the United States wants free and open access.