Vietnam and China signed 10 agreements on Oct 13, including on expanding cross-border railway links, payments and economic cooperation. The signings followed a meeting between Vietnamese Prime Minister Pham Minh Chinh and visiting Chinese Premier Li Qiang. They agreed to work on a technical plan for a rail link between Lao Cai in northern Vietnam and Hekou in China's Yunnan province.

The two sides also signed a memorandum of understanding (MoU) on the implementation of cross-border payment services via QR codes and an agreement to study a model for an "economic cooperation zone" across their border.

China is Vietnam's biggest trade partner, but the two countries share historic tensions -  including in the South China Sea, a waterway through which trillions of dollars of trade pass each year. Vietnam's top leader To Lam and Li agreed on Saturday to boost defence and economic cooperation, Vietnamese state media reported.

The two agreed to "maintain regular high-level exchanges and cooperation in defence, security, and foreign affairs ... expanding the implementation of new mechanisms", the Nhan Dan newspaper said.

Vietnam would facilitate more high-tech Chinese investment in the country and Beijing would strengthen market access for Vietnamese agricultural products, the newspaper said.