Liberia closed its border with Guinea this week after a flare-up of Ebola in Guinea, Information Minister Lenn Eugene Nangbe told dpa on Tuesday.
The closure of the borders on Monday was a precautionary measure to prevent the spread of Ebola from Guinea into Liberia, Nangbe said.
"We have sent military, police and medical personnel and increased surveillance in the towns and villages along the border, which is very porous," he said.
He said the borders would remain closed until further notice.
"Any additional action on the part of Liberia will be informed by the situation in Guinea," he said. "We will react accordingly."
Medical personnel are already moving through border towns and villages conducting screening for Ebola cases.
Guinea's National Coordinating Unit for the Fight against Ebola said Tuesday it is monitoring 997 people in the southern village of Koropara after a flare-up of Ebola last week.
The West African nation has recorded two confirmed cases of Ebola since it was declared Ebola free at the end of December, Fode Tass Sylla told dpa from the capital Conakry.
The two family members were confirmed to have died from Ebola in Guinea on Friday, two days after the World Health Organization said the region was "effectively managing" the virus.
WHO said last week that all original chains of transmission in the epidemic have been halted, but that small flare-ups are anticipated because of virus persistence in the fluids and tissues of some survivors
The Ebola outbreak in West Africa, which started in Guinea in December 2013, was the largest in history, spreading to Sierra Leone, Liberia and Nigeria.
It also reached Europe and the United States, where isolated cases of the disease were reported.
More than 11,300 people have died since the outbreak started, while 28,500 have been infected, according to the WHO's latest figures.
Sierra Leone was declared free of Ebola transmission on November 7, Guinea on December 29 and Liberia on January 14.
Ebola, which was discovered in 1976 and is passed on through contact with blood and other bodily fluids, causes massive hemorrhaging and has a fatality rate of up to 90 per cent if left untreated.