Rwanda's health ministry on Monday urged citizens to avoid unnecessary travel to eastern Democratic Republic of Congo after a case of Ebola was discovered in a city straddling its border.
The case was detected in Goma, a city of around one million that is separated by a border crossing from the town of Gisenyi, in western Rwanda.
Goma is the biggest urban hub to have been affected by Ebola since an outbreak that has killed more than 1,600 people began in DR Congo's North Kivu province last August.
The crossing between Goma and Gisenyi is one of the most traversed in the region, with thousands making the journey back and forth each day.
The health ministry said while no cases of Ebola had been detected in Rwanda, it was vital citizens played their part in helping prevent the spread of the deadly disease.
"The ministry of health reminds citizens and residents not to make unnecessary border crossings and travels to areas in neighbouring countries where Ebola has been reported," the ministry said in a statement.
"We also advise that citizens and residents should not provide unnecessary accommodation to travellers who are coming from areas of neighbouring countries where Ebola has been reported."
Health Minister Diane Gashumba, who visited towns along Rwanda's western frontier on Monday, said the government "would not close the border" but would bolster monitoring of those coming in and out of DR Congo.
Almost all the victims in this outbreak -- the second-worst in Ebola's history -- were from DR Congo.
Two people who crossed from DR Congo into Uganda also died in June, but that country has now declared itself Ebola-free.
Experts fret when a contagious disease occurs in a city, where contact, mobility and anonymity make it far harder to contain an outbreak than in the countryside.
The Goma patient was described as a pastor who had been on a trip to Butembo, one of the towns hardest hit by the outbreak in North Kivu.
There, he preached at seven churches and regularly touched worshippers, "including the sick," the country's health ministry said.
His symptoms first surfaced last Tuesday, it said.
Ebola spreads when humans touch the blood, body fluids, secretions or organs of an infected person, or objects contaminated by such fluids.