BEIJING — A ruling Chinese Communist Party newspaper on Monday denounced the passage of a pair of U.S. Navy ships through the Taiwan Strait as a “psychological game,” as the two sides square off over trade and relations with self-governing Taiwan.

The Global Times said in an editorial that the U.S. was adding to tensions by sailing the Japan-based guided missile destroyers USS Mustin and USS Benfold through the 160-kilometer-wide (100-mile-wide) strait that divides Taiwan from mainland China.

Though such missions are not uncommon, both Taiwan and the U.S. made unusual public confirmations of the ships’ passage over the weekend.

Washington is “sending political signals by sending warships through the Taiwan Strait,” said the Global Times editorial, headline “U.S. psychological game in Taiwan Strait.”

At a daily briefing Monday, Foreign Ministry spokeswoman Hua Chunying said China had “played close attention to” the passage of the ships, but declined to connect the incident to other issues affecting relations between Beijing and Washington.

A medium-long range surface-to-air missile launches from the missile deck of Arleigh Burke-class guided-missile destroyer USS Mustin (DDG 89) during MultiSail17 on March 7, 2017, in the Pacific. (MC3 Christopher A. Veloicaza/Navy)
A medium-long range surface-to-air missile launches from the missile deck of Arleigh Burke-class guided-missile destroyer USS Mustin (DDG 89) during MultiSail17 on March 7, 2017, in the Pacific. (MC3 Christopher A. Veloicaza/Navy)

China, which claims Taiwan as its own territory to be conquered by force if necessary, has criticized recent U.S. moves to strengthen relations with the administration of Taiwanese President Tsai Ing-wen. Those include the opening of a new office complex for the American Institute in Taiwan, which operates as Washington’s de facto embassy on the island in the absence of formal diplomatic ties that were cut when the U.S. switched recognition to China in 1949.

The U.S. Congress recently passed a law encouraging higher-level government contacts between the sides and closer cooperation between their militaries is also being emphasized.

Such developments come amid rising frictions over what the U.S. considers unfair trading practices by China, the world’s second-largest economy.

The administration of President Donald Trump imposed a 25 percent tax on $34 billion worth of Chinese imports on Friday. China is retaliating with taxes on an equal amount of U.S. products, including soybeans, electric cars and pork.

A former Japanese colony, Taiwan split from China amid civil war in 1949 and China cut off relations with Tsai’s government after her 2016 inauguration because she refuses to recognize the island as a part of China.

Despite the lack of diplomatic relations, the U.S. remains Taiwan’s chief international ally and American law requires the government to respond to threats to the island.