Bamako - Fearful of a surge of Ebola cases, Mali placed nearly 600 people under surveillance, as the country battles to contain the spread of the deadly tropical virus.
Malian officials met on Monday to consider increasing security at its border following two confirmed cases of Ebola due to infection in neighbouring Guinea.
US airports also announced plans to begin enhanced screening of travellers from the west African nation.
Mali has been scrambling to prevent a minor outbreak from turning into a major crisis after the deaths of a Guinean imam and the Malian nurse who treated him in the capital Bamako.
Teams of investigators
A friend who had visited the imam in the Pasteur clinic also died of probable Ebola, and a two-year-old child died from the disease last month in an unconnected case in the western town of Kayes.
President Ibrahim Boubacar Keita, on a visit to the imam's home village of Kouremale on the Mali-Guinea border, urged locals to take all precautions in "the war" against Ebola.
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Health Minister Ousmane Kone, who accompanied the president on the trip, said "577 people were under daily observation", up from Sunday's figure of 442 people who were being monitored for Ebola symptoms.
Teams of investigators have been tracking health workers and scouring Bamako and the imam's village of Kouremale, which straddles the Mali-Guinea border, for people who could have been exposed.
Public awareness measures
The European Union on Monday pledged $15m in funding to Mali, Senegal and Ivory Coast amid growing fears Ebola could spread in the region.
The money would help the countries "prepare for the risk of an Ebola outbreak through early detection and public awareness measures".
The World Health Organisation announced on Friday that the outbreak - almost entirely confined to west Africa - has killed 5 177 people and infected around 14 500 since Ebola emerged in Guinea in December.
The death rate in west Africa from the virus has reached around 70%, the World Health Organisation said on Tuesday.
US authorities on Monday began enhanced Ebola screenings of travellers from Mali, adding it to a list of three other west African countries - Liberia, Sierra Leone and Guinea - where the measures were already in place.
The US Centers for Disease Control and Prevention, in a joint statement with the Department of Homeland Security, said Mali was added to the list "because there have been a number of confirmed cases of Ebola" there in recent days.
"A large number of individuals may have been exposed to those cases," the statement said.
"The action is warranted as a precaution due to the possibility that other cases of Ebola may emerge in Mali in the coming days," the statement said.
21-day monitoring and movement protocols
The United States said about 15-20 travellers depart Mali each day en route to the United States.
Also Read: Sierra Leone doctor dies of Ebola at Nebraska hospital
Those arriving will be checked for fever and subject to the 21-day monitoring and movement protocols already in effect for travellers from Liberia, Sierra Leone and Guinea.
Meanwhile, a cargo ship on its way from Guinea to Ukraine reported it had a crew member with possible symptoms of Ebola, and prepared to drop anchor off Athens so doctors could board to examine him.
If confirmed, it would be the first case in Greece of the hemorrhagic virus.
And in Guinea, the United Nations envoy charged with leading the Ebola response in that country, Rwandan national Marcel Rudasingwa, died on Monday.
Surgeon is mourned
Meanwhile, in Nebraska, medical staff mourned the death of a surgeon infected in Sierra Leone who died about a day after being airlifted to a specialised US hospital.
Martin Salia, 44, was a US resident who had been working at a hospital near Freetown. The married father of two was suffering multiple organ failure by the time he arrived in the United States on Saturday.
"Dr Salia was extremely critical when he arrived here, and unfortunately, despite our best efforts, we weren't able to save him," said Phil Smith, medical director of the bio-containment unit at the University of Nebraska Medical Centre.
In Washington, the White House extended condolences to the doctor's family, praising him as a man who "dedicated his life to saving others".
"Dr. Salia's passing is another reminder of the human toll of this disease and of the continued imperative to tackle this epidemic on the frontlines, where Dr. Salia was engaged in his calling," White House press secretary Josh Earnest said.
A spokesman for Sierra Leone's government, Abdulaye Bayratay, said it was "so sad for us to lose another doctor".
Salia and his wife, Isatu, lived in New Carrollton, Maryland, a suburb of the US capital Washington. They have two children, aged 12 and 20.