In the 1970s, Vietnam invaded Cambodia and installed a pro-Vietnamese government in Phnom Penh. The Vietnamese occupation lasted for over a decade, and during this time, Vietnam annexed some Cambodian territory, including the Mekong Delta region.
After the Vietnamese withdrew from Cambodia in 1989, the two countries agreed to a ceasefire and began negotiations to resolve their border dispute. However, the negotiations have been slow and difficult, and the two countries have not yet reached a final agreement.
In the meantime, the border between Vietnam and Cambodia remains a source of tension. There have been several outbreaks of violence along the border, and the two countries have accused each other of violating the ceasefire.
The border dispute between Vietnam and Cambodia is a complex and sensitive issue. It is a source of tension between the two countries, and it has the potential to lead to future conflict.