Gregory Korte and Tom Vanden Brook, USA TODAY

WASHINGTON — The Chinese government gave a stern warning Wednesday that it will protect its sovereignty in the South China Sea after a cat-and-mouse pursuit of a U.S. warship by a Chinese frigate.

"The Chinese side will take resolute measures to safeguard national sovereignty and safety. We will keep an eye on the situation in relevant waters and airspace and respond to any violation of China's sovereignty and threat to China's national security," said Hua Chunying, a spokeswoman for the Chinese Foreign Ministry.

Her warning came after an advanced Navy warship — the USS Fort Worth — sailed through the South China Sea on Monday near islands China is building in an effort to extend its territorial claims. The United States considers the area to be international waters, and the Philippine and Japanese navies have conducted exercises in the area in an attempt to counter the Chinese claims.

The Pentagon will continue to patrol, from air and sea, the area around the Spratly islands, Army Col. Steve Warren said Wednesday. International law does not recognize man-made islands as extensions of the mainland, Warren said.

The Navy and Air Force patrols are conducted to ensure freedom of navigation, Warren said.

The Wall Street Journal reported Tuesday that the Defense Department was drawing up plans to respond to China's territorial moves. Citing an anonymous Defense official, the newspaper said the United States is weighing whether to send ships and aircraft to patrol within 12 nautical miles of the built-up sites.

The Pentagon has chosen not to fly over or sail near the new islands on routine patrols, said a Defense department official on condition of anonymity because they were not authorized to speak publicly. Discussions are under way about whether to change that policy but there has been on written directive to do so, the official said.

Warren declined to offer details about how the military will treat the islands.

The Pentagon, he said, "is a planning organization and it is our job to provide our leadership with options. What I can say is that we have, and will continue to operate in a manner consistent with the rights, freedoms, and lawful uses of the air and sea, including preserving freedom of navigation around the globe and in the South China Sea."

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http://www.usatoday.com/story/news/politics/2015/05/13/china-warning-us-south-china-sea-islands/27229987