China's second-ranking general has recently visited the country's man-made islands in the South China Sea that the U.S. and others have criticized for raising tensions in the region.

The Defense Ministry said in a brief statement Friday that Fan Changlong led a group of military commanders to the Spratly island group to visit troops and observe construction work. The statement didn't say exactly when and where Fan visited.

The announcement comes after China issued an angry response to what it says are provocative plans for stepped-up U.S.-Philippine military cooperation that includes joint naval patrols.

U.S. Defense Secretary Ash Carter was also visiting an aircraft carrier in the South China Sea on Friday during a trip to the region that does not include a stop in China.