China and Vietnam have signed a joint communique pledging to improve cooperation and demarcation talks regarding disputes in the South China Sea. The document also indicated that their ruling parties plan to reinforce each other's leadership through a new five-year action plan.

Beijing and Hanoi have bolstered their commitment to demarcation talks over a contested stretch of water in the South China Sea, pledging to “better” navigate bilateral frictions in the area, according to a joint communique. The document also said the countries’ ruling communist parties had agreed to shore up each other’s leadership at home with the adoption of a new five-year action plan. Published on Friday as To Lam, Vietnam’s top leader, wrapped up his four-day visit to China, the communique...