Updated Oct. 27 at 3:00 pm in Hong Kong with the Chinese Foreign Ministry’s statement. This article has been corrected.

The United States sent a warship through disputed waters claimed by several countries, but which China considers entirely its own territory, and had pledged to defend. The USS Lassen, a guided-missile destroyer, sailed within 12 nautical miles of an island built on the Subi reef in the Spratly islands, a US defense official told USA Today.

China has transformed once submerged reefs in disputed waters in the South China Sea into islands that it claims as its own territory. Because the USS Lassen passed within 12 nautical miles of the man-made islands, the distance international maritime laws define as an island’s sovereign waters, the move essentially demonstrates that the US does not respect these claims.

Read more: http://qz.com/533756/the-us-just-challenged-china-in-the-south-china-sea-and-nothing-happened/