A high-ranking Chinese Communist Party official traveled to Vietnam and met the country's supreme leader on Tuesday.
The meeting happened five days before US President Joe Biden is scheduled to visit Hanoi.
Vietnam's state-run agency issued a report about the talks between Liu Jianchao and Nguyen Phu Trong, Vietnam's Communist Party General Secretary. Trong reportedly stressed that the two countries are friends.
He also thanked Chinese President Xi Jinping for contributing to the development of bilateral ties in recent years.
Liu is the head of the International Department of the Communist Party's Central Committee. He agreed to strengthen bilateral ties and continue promoting cooperation between the two parties.
China and Vietnam have been engaged in a territorial dispute over the South China Sea. But Vietnam's leader visited Beijing last October.
He held talks with his Chinese counterpart and highlighted bilateral ties between the nations.
The United States regards China as its biggest competitor. It has also been strengthening ties with Vietnam.
The US president is scheduled to visit the capital and hold talks with the country's top leaders on Sunday. Biden will go there after he leaves India.
Vietnam is trying to strike a balance between the two superpowers by emphasizing its relations with China ahead of Biden's visit. Beijing and Hanoi have strong economic ties.