Story highlights U.S. didn't intend to go within 12 miles of an artificial Chinese island, official says

In October, the Chinese complained when a ship sailed close to island

(CNN) China is once again complaining that the United States violated its sovereign territory by coming near artificial islands in the South China Sea.

This time the problem occurred when a U.S. military flight strayed into disputed airspace near the islands, a senior U.S. defense official told CNN.

The United States did not intend to get within 12 nautical miles of the land, the official said, and the flight was not part of a "freedom of navigation" mission like the one that occurred in late October.

That put the vessel within an area that would be considered Chinese sovereign territory -- if the United States recognized the islands as being Chinese territory, a U.S. official told CNN in October.

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