May 24 (UPI) -- Two U.S. Navy ships moved through the Taiwan Strait this week, adding to tensions with China amid a trade dispute between the two nations.
This is the fifth time this year U.S. warships have sailed through 110-mile wide strait separating Taiwan from the Chinese mainland.
The Arleigh Burke-class guided-missile destroyer USS Preble and fleet replenishment oiler USNS Walter S. Diehl traveled through the waters Wednesday and Thursday, U.S. Seventh Fleet public affairs officer Clay Doss told Bloomberg News.
"The ships' transit through the Taiwan Strait demonstrates the U.S. commitment to a free and open Indo-Pacific," Doss said. "The U.S. Navy will continue to fly, sail and operate anywhere international law allows."
The U.S. warships sailed north through the strait by following a standard course and nothing out of the ordinary occurred, Taiwan's Ministry of National Defense said in a statement obtained by Taiwan News.
China reacted negatively to the passage, as it has in the past.
"We have expressed our concern to the U.S. side," Foreign Ministry spokesman Lu Kang said during a regularly scheduled press briefing Thursday.
China "has been closely monitoring from start to end the passage by the U.S. warships through the Taiwan Strait," he said.
With the Taiwan issue "the most important and sensitive one in China-U.S. relations," 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."
This is the second time this week a passage by the USS Preble angered China.
On Monday, the Pearl Harbor-based ship sailed within 12 nautical miles of the South China Sea's Scarborough Shoal, which is controlled by China but also claimed by Taiwan and the Philippines, the Honolulu Advertiser reported.
The United States does not recognize the shoal as China's territory.
China China's foreign ministry disagrees, saying the Preble "trespassed into the adjacent waters" without permission from the Chinese government.
"The Chinese Navy identified and verified the U.S. warship according to law, and warned it off," Lu said about the area it calls Huangyan Dao. "I have to stress again that the trespass of U.S. warship is a violation of China's sovereignty."
The United States wants free and open access through the South China Sea with an estimated $3.4 trillion worth of international shipping each year.
Trade talks broke off earlier this month between the United States and China.
The United states raised tariffs on $200 billion worth of Chinese goods from 10 percent to 25 percent and plans to implement 25 percent tariffs on all remaining Chinese goods in the near future. China retaliated with tariffs on $60 billion worth of U.S. products.