As world leaders met to discuss the Ebola outbreak at the United Nations, Sierra Leone began a quarantine of more than one million people in the largest lockdown of the epidemic.
The northern districts of Port Loko and Bombali were to be closed off along with the southern district of Moyamba -- effectively sealing in around 1.2 million people.
With the eastern districts of Kenema and Kailahun already under quarantine, more than a third of the population of six million, in five of the nation's 14 districts, now finds itself unable to move freely.
"The isolation of districts and chiefdoms will definitely pose great difficulty but the lives of everyone and the survival of our country takes precedence over these difficulties," President Ernest Bai Koroma told the nation in a televised address late Wednesday.
"These are trying moments for everyone in the country."
- 'Horrific suffering' -
The deadliest Ebola epidemic on record has infected more than 6,200 people in west Africa and killed nearly half of them, according to the World Health Organization's latest figures.
The virus can fell its victims within days, causing rampant fever, severe muscle pain, vomiting, diarrhoea and -- in many cases -- unstoppable internal and external bleeding.
In Sierra Leone, Ebola has infected 1,940 people, killing 593, by the WHO count, but the UN agency has warned the number of cases across the region could explode in the coming months without an urgent response.
World leaders were due to attend a meeting in New York on Ebola convened by United Nations Secretary-General Ban Ki-moon later Thursday, with Koroma and Liberia's President Ellen Johnson Sirleaf connected by video link.
The meeting -- part of the United Nations General Assembly -- will hear from US President Barack Obama and world leaders are expected to pledge help for efforts to try to contain the spread of the virus.
Obama, who is sending 3,000 troops to west Africa to aid local health workers battle the contagion, urged other countries Wednesday to get behind a broader international effort.
In a speech to the General Assembly, Obama grouped Ebola with the crisis in Ukraine and the threat posed by Islamic State group jihadists in Iraq and Syria as "new dangers" that imperil global security.
"As we speak, America is deploying our doctors and scientists -- supported by our military -- to help contain the outbreak of Ebola and pursue new treatments," Obama told the 193-member assembly.
"But we need a broader effort to stop a disease that could kill hundreds of thousands, inflict horrific suffering, destabilise economies and move rapidly across borders."
The WHO warned Tuesday that without quicker prevention efforts, hundreds of thousands could be infected with Ebola by the end of the year.
The US Centers for Disease Control estimated that cases in Liberia and Sierra Leone could rocket to 1.4 million by January -- in a worst-case scenario based on data obtained before the world ramped up its response.
- Ending the outbreak -
Sierra Leone has revealed that around 100 bodies and 200 patients were collected from homes during a nationwide three-day lockdown and house-to-house information campaign which ended on Sunday.
Koroma said in his televised address the temporary curfew had prompted the new quarantine -- which is expected to remain in place until the crisis is under control.
The president said 12 of the county's 149 tribal chiefdoms -- much smaller administrative areas than districts -- were also to be placed in quarantine. The total population in these areas was not immediately clear.
He announced that corridors for travel to and from non-quarantined areas had been established but would only operate between 9:00 am and 5:00 pm.
The lockdown was "line with our people's avowed commitment to support extra measures to end the Ebola outbreak," Koroma said.
"The Ministry of Health and Sanitation and the emergency operation centre will establish additional holding centres in the quarantined chiefdoms," he added.
The WHO said on Thursday that 6,263 people had been infected since the virus first emerged in southern Guinea in December, and that 2,917 had died.
In Liberia, which has been hit hardest by the outbreak, 3,280 people have been infected and 1,677 have died while in Guinea, Ebola has infected 1,022 people, killing 635.
Nigeria has recorded 20 cases, including eight deaths, since the virus first arrived in the country with a Liberian finance ministry official, who died in Lagos on July 25.
Nigerian President Goodluck Jonathan told the General Assembly on Wednesday that Nigeria was free of Ebola, appearing to jump the gun on medical advice at home to wait before giving the all-clear.