China and Vietnam announced on Wednesday they had settled their long disputed land border, only hours before a deadline was due to expire and nearly 30 years after they fought a border war.
Government teams from both sides have worked for years to plant border stones to mark their approximately 1,400km frontier in the remote and mountainous region, to meet a 2008 deadline agreed nine years ago.
On New Year's Eve, hours before the midnight deadline, both sides issued a joint statement in Hanoi saying they had finalised the demarcation and placement of markers along the entire land border between Vietnam and China, AFP reports.
The countries, represented by Chinese Vice Foreign Minister Wu Dawei and his Vietnamese counterpart Vu Dung, hailed the agreement as "an event of great historical significance for relations between Vietnam and China."
They said it was the first time China and Vietnam had defined a clear territorial border with modern landmarkers, and they pledged to work for "peace, stability and mutual development in the border areas."
Almost 30 years ago China invaded Vietnam, sparking a month-long border war that claimed tens of thousands of lives.
The border area remains littered with landmines which, according to a Xinhua report this week, have killed and maimed thousands of Chinese since.
The two countries normalised relations in 1991 and are now major trade partners.
They have sought to overcome a history of conflict and distrust to turn the former battlefields into a transnational economic growth area.
Under the plan, Vietnam's poor far-north is set to be transformed with industrial projects and new road and rail links that would connect China's Yunnan and Guangxi provinces with Vietnam's Haiphong seaport.
The economic corridors, part of a web of highways linking China with South-East Asia, would help boost annual two-way trade to a targeted $US25 billion by 2010 from $US16 billion last year.