TAIPEI (Reuters – On Tuesday, a U.S. Warship passed through Taiwan Strait. It was part of routine U.S. activity that China considers to be routine but always riles China. China believes Washington seeks regional tensions.

According to the U.S. Navy, Milius (an Arleigh Burke-class guided missile destroyer) conducted an “accurate Taiwan Strait transit” in international waters. This was consistent with international law.

The U.S. is committed to a free Indo-Pacific. “The vessel’s passage through Taiwan Strait demonstrates that commitment.” It added that the United States military “flies, sails and operates wherever international law permits”

China didn’t immediately reply.

The Chinese military condemned last month the United States, Canada, and Japan for sending warships through Taiwan Strait. They claimed they threatened peace and stability within the region.

China asserts Taiwan is democratically controlled by it and has launched numerous air force operations into Taiwan’s Air Defence Identification Zone (ADIZ) in the last year, angering Taipei.

Although the United States does not have diplomatic relations with Taiwan, it is an important backer of its arms supply and international support.

Beijing considers Taiwan to be the most important and sensitive issue in Washington’s relations.

The U.S. Navy has been passing through the strait about monthly to the dismay of Beijing. Sometimes, ships are also sent by U.S. allies through the Strait. This includes Britain in September.