U.S. Vice President Joe Biden has told a top Chinese military official that Beijing's actions the South China Sea are dangerous and provocative.
Biden met in Washington Thursday with the Chinese military's chief of staff, General Fang Fenghui.
Biden told Fang that China cannot undermine security and peace.
China deployed an oil rig last month in a part of the South China Sea that Vietnam claims is within its exclusive economic zone.
The dispute has led to anti-Chinese protests in Vietnam, including a riot at Taiwanese steel plant that killed a Chinese worker and injured 149 other people.
Chinese and Vietnamese ships have attacked each other with water cannons, raising fears of an all-out military clash.