A U.S. Navy warship sailed through the contested waters separating Taiwan and mainland China on Sunday just days after Beijing concluded week-long war games around the self-ruled, independent island.

The U.S. 7th Fleet said the transit by the Arleigh Burke-class guided-missile destroyer USS Milius (DDG 69) was routine. The warship “transited through a corridor in the Strait that is beyond the territorial sea of any coastal State,” a statement outlined, adding:

Milius’ transit through the Taiwan Strait demonstrates the United States’ commitment to a free and open Indo-Pacific. The United States military flies, sails, and operates anywhere international law allows.

This was the first such U.S. operation through the waterway since January.

Images shared Monday on social media of U.S. Navy showed crew looking out into the strait, one of the most crucial waterways in the world for international shipping.

China’s ruling Communist Party protested by saying the U.S. transit was a “public hype” before asserting the Eastern Theater Command was ready at any time to “resolutely safeguard the country’s sovereignty, safety, and regional peace and stability,” according to a statement from the Eastern Theater Command’s spokesperson Shi Yilu as reported by AP.

Last week China concluded large-scale air and sea drills in the strait in retaliation for Taiwan’s President Tsai Ing-wen meeting with U.S. House Speaker Kevin McCarthy in California, as Breitbart News reported.

China said the exercises simulating an encirclement of Taiwan were intended as a “serious warning” to pro-independence politicians on the self-governing island and their foreign supporters.

Taiwan and mainland China split in 1949 after a civil war with the former immediately proclaiming its independence.

Beijing says the island is obligated to rejoin the mainland, by force if necessary, while Taiwan maintains freedom and democracy triumph over Communist dictatorship and refuses to yield.