The Dominican government has alleged that a Haitian-built canal threatens to divert its water and harm its farmlands.
President Luis Abinader issued the order on Monday, citing construction work on a Haitian canal that Dominican officials say will divert water from the Massacre River, which runs in both countries.
“If the conflict is not resolved before Thursday, [officials will] completely close the border to air, sea and land commerce,” the government said in a statement.
The announcement is the latest chapter in a long history of friction between the two countries, which share the same island of Hispaniola but are split by ethnic, linguistic and cultural divisions.
In an unusual complication, it remains unclear who authorised work on the canal in Haiti.
The Dominican government said it believes Haitian citizens are acting unilaterally to build the waterway, without the approval of their local officials.
In Monday’s statement, the Dominican government framed the situation as an indication of the instability on the other side of the border.
“The Haitian government has repeatedly admitted it does not have the capacity to resolve internal conflicts due to the loss of the Haitian state’s monopoly on force due to criminal organizations,” it said.
Haiti has indeed seen an uptick in gang violence in recent years, particularly in the wake of the assassination of President Jovenel Moïse in 2021. No federal elections have been held in recent years, contributing to a power vacuum that criminal organisations had taken advantage of.
The United Nations estimated last December that at least 60 percent of the Haitian capital Port-au-Prince had fallen under gang control.
The resulting violence has forced tens of thousands of Haitians to flee their homes, with some seeking safety across the border in the Dominican Republic, another source of tension between the two countries.
Abinader has stepped up efforts to restrict immigration, including through the construction of a border barrier between the two countries. He has also ramped up deportation efforts.
William Charpantier, coordinator for MENAMIRD, a national roundtable for migrants and refugees in the Dominican Republic, told Al Jazeera that 20,000 people were expelled in a nine-day period last year.
Some, he said, were not even Haitian but were rather Dominican citizens targeted because of their skin colour. Haiti is a predominantly Black country, while the majority of Dominicans identify as mixed race.
“These deportations have resulted in the separation of families. People with valid documents have been deported, people who were born here in the Dominican Republic have been deported,” Charpantier said. “These aren’t deportations. It’s persecution based on race.”
Experts warn that, if the Dominican Republic follows through on Monday’s threat to fully seal the border, it could have a devastating impact on the already impoverished Haiti, which relies heavily on imports from its neighbour.
The move could even harm the Dominican economy. Haiti serves as the country’s third-largest trading partner and informal trade across the border likewise results in millions of dollars in profit.
A study from the Dominican Republic’s Central Bank estimated that, in 2017, the informal trade amounted to approximately $430m in commerce. Of that figure, $330m was in exports to Haiti.
Last week, Abinader ordered a vital crossing near the town of Dajabon closed after reports of excavation work on the canal, which Dominican officials worry could harm farmland and the environment.
The government has said that it will seek talks with Haiti to find a “definitive solution”.