China urges U.S. to act cautiously

China is still trying to verify whether a U.S. warship went within 12 nautical miles of Chinese-controlled islands in the South China Sea but, if true, the United States must think carefully, China's Foreign Minister said on Tuesday.

"If true, we advise the U.S. to think again and before acting, not act blindly or make trouble out of nothing," the foreign ministry quoted Foreign Minister Wang Yi as saying.

The patrol by the USS Lassen was the most significant U.S. challenge yet to 12-nautical-mile territorial limits China asserts around the islands in the Spratly archipelago and could ratchet up tensions in one of the world's busiest sea lanes.