China and Vietnam will manage and properly control their maritime disputes, avoiding actions to complicate or widen them, so as to maintain peace in the South China Sea, the two nations said in a joint communique China released on Monday.
Vietnam is the Southeast Asian country most openly at odds with China over the waterway since the Philippines pulled back from confrontation under President Rodrigo Duterte.
After what China said were "positive" talks on the South China Sea last week between President Xi Jinping and Vietnamese President Tran Dai Quang, the joint statement stressed the need to control differences.
Both countries agreed to "manage and properly control maritime disputes, not take any actions to complicate the situation or expand the dispute, and maintain peace and stability in the South China Sea", it added.
The document, released by the Chinese Foreign Ministry, said both had a "candid and deep" exchange of views on maritime issues, and agreed to use an existing border talks mechanism to look for a lasting resolution.
China claims 90 percent of the potentially energy-rich South China Sea. Besides Vietnam, Brunei, Malaysia, the Philippines, and Taiwan lay claim to parts of the route, through which about $5 trillion of trade passes each year.
Last year, tension between Beijing and Hanoi rose after Taiwan and U.S. officials said China had placed surface-to-air missiles on Woody Island, part of the Paracels archipelago it controls.
Vietnam called China's actions a serious infringement of its sovereignty over the Paracels.
In 2014, tension between the two communist countries peaked more dramatically when China moved an oil rig into disputed waters and protests broke out across Vietnam.
Relations have gradually improved since, with exchanges of high-level visits, though the regional military buildup continues, including China's construction of airstrips on man-made islands in the busy waterway.
Quang arrived in Beijing last week for a state visit and to attend a two-day conference ending Monday on an ambitious scheme proposed by Xi to build a new Silk Road connecting China to Asia, Europe and beyond, through massive infrastructure investment.
Reporting by Ben Blanchard