The Rwanda government has shut its border with the Democratic Republic of Congo (DRC) at the point of Goma.
According to a statement from the DRC presidency, Rwanda’s decision was done without consultation and agreement from both countries.
In a statement, it said there had been a "unilateral decision by the Rwandan authorities" that affected citizens from both countries who had to cross the border as part of their daily lives.
"On the basis of a unilateral decision by the Rwandan authorities, Rwandan citizens cannot go to Goma and Congolese cannot leave Gisenyi but are prevented from going home," the statement said.
"This decision harms a number of Congolese and expatriates who live in Gisenyi but work in Goma,” the statement continued.
Goma, a city of two million people and a major transport hub, shares the border with the Rwandan city of Gisenyi, which has a population of more than 85 000.
Cross-frontier links are intense. Many people have jobs on the other side of the border while others have homes or put their children in schools in the neighboring city.
The announcement came just hours after the third case of Ebola was recorded in Goma, widening the scope of the epidemic on its first anniversary.
Early this year, Rwanda unilaterally closed its border with Uganda citing a number of issues.