Vietnam and China signed a 16-page joint declaration and 36 co-operation documents in areas such as infrastructure, trade and security, during a visit to Hanoi by Chinese President Xi Jinping.

Chinese President Xi Jinping attends a lay wreath ceremony at the Ho Chi Minh mausoleum during a two day state visit to Hanoi.

Half the agreements signed this week by the Communist-ruled countries were non-binding. Their content was not made public. The list of deals covers topics such as rail links and security.

Here are of some of the most important signings:

INFRASTRUCTURE & RAIL LINKS

* Memorandums of understanding (MoUs) on strengthening Vietnam-China railway cooperation and aid for cross-border railway development

* An agreement on jointly building a new bridge across the Red River to connect Vietnam's Lao Cai province and China's Yunnan province

* A commitment in the joint statement to the two countries working on the construction of interoperable railways connecting China to the Vietnamese northern port of Haiphong.

DEFENCE & SECURITY

* MoU on joint naval patrols in the Gulf of Tonkin

* An agreement on establishing a hotline between Vietnam's agriculture ministry and China's coastguard for handling unexpected incidents arising from Vietnam's fisheries activities in the South China Sea (in addition to an earlier pledge to enhance an existing hotline between defence ministries)

* An agreement on the extradition of prisoners and people convicted of crimes

* An agreement on conducting joint search-and-rescue operations at sea

* A commitment in the joint statement to boosting security and intelligence cooperation, including against "hostile forces".

DIGITAL, DATA & TELECOMMUNICATIONS

* MoUs on cooperation and investment in the digital economy and data

* An MoU on cooperation in telecommunications, information technology, communications and digital transformation.

TRADE & INVESTMENT

* MoU on enhancing development cooperation and promoting the implementation of the Global Development Initiative, a Chinese initiative to promote global economic growth

* MoU on promoting investment cooperation in green development

* Action plans until 2026 on the implementation of previous MoUs between Vietnam and China's southern province of Yunnan and the autonomous region of Guangxi on enhancing economic and trade cooperation

* In the joint statement the two nations pledged to develop an economic zone to boost trade and investment.