Vietnam's president is being feted by China's leaders on a visit through Friday as Beijing continues to shun another rival for South China Sea territory that has challenged its claims on legal grounds, the Philippines.

President Truong Tan Sang is on the three-day visit to boost economic ties with China, Vietnam's communist ally and biggest trading partner. How to manage their disputed territorial sea claims is also on the agenda.

China and Vietnam agreed on Wednesday to set up a hotline to resolve fishing incidents in their disputed waters. Both sides should inform the other of any detentions or incidents involving fishermen or fishing boats within 48 hours.

China claims virtually the entire South China Sea and its island groups, while Vietnam and other Southeast Asian countries claim some areas.