The World Health Organization warned Monday that Liberia is set to see a huge spike in infections from the Ebola epidemic ravaging west Africa, with thousands of new cases imminent.
The UN agency said the country, worst-hit in the outbreak with almost 1,100 deaths, faced "many thousands" of new infections in the next three weeks.
"WHO and its director-general will continue to advocate for more Ebola treatment beds in Liberia and elsewhere, and will hold the world accountable for responding to this dire emergency with its unprecedented dimensions of human suffering," it said in a statement.
The deadliest Ebola epidemic the world has ever seen is spreading across west Africa, with Liberia, Guinea and Sierra Leone the countries worst affected.
The death toll has topped 2,000, out of nearly 4,000 people infected.
Liberia already accounts for about half of all cases and deaths, and "the number of new cases is increasing exponentially", the WHO warned.
Key development partners trying to help Liberia respond to the outbreak "need to prepare to scale up their current efforts by three- to four-fold," it added.
The countries bearing the brunt of the epidemic are among the world's poorest, with dilapidated medical infrastructures that have all but buckled under the strain of trying to contain the virus.
Before the outbreak, Liberia had only one doctor to treat every 100,000 patients in a total population of 4.4 million people.
Now that 152 healthcare workers in the country have been infected and 79 have died, the WHO said the ratio had worsened significantly.
"Every infection or death of a doctor or nurse depletes response capacity significantly," it said.
The UN body described how taxis filled with entire families, including members suspected of having Ebola, criss-crossed Monrovia "searching for a treatment bed".
"There are none. As WHO staff in Liberia confirm, no free beds for Ebola treatment exist anywhere in the country."
When Ebola patients are turned away from treatment centres, "they have no choice but to return to their communities and homes, where they inevitably infect others, perpetuating constantly higher flare-ups in the number of cases," it said.
In Montserrado county alone, which includes Monrovia, the agency said 1,000 beds were urgently needed to treat Ebola patients.
In the scramble to halt the contagion, some affected countries have quarantined whole regions, while others so far free of the virus have halted flights.
African Union commission chief Nkosazana Dlamini-Zuma called Monday for travel bans imposed to stem the epidemic to be lifted, "to open up economic activities".
She told a crisis meeting in Addis Ababa there was an urgent need to "craft a united, comprehensive and collective African response" to the outbreak.
But she also warned that in the battle to stop the spread, "we must be careful not to introduce measures that may have more... social and economic impact than the disease itself".
Experts have warned that economic losses caused by the restrictions were adding to the continent's woes, with some arguing that travel bans even slowed medical help getting to affected areas.
Border restrictions are also hampering trade and food prices are rising, Dlamini-Zuma said, echoing the UN's warning of serious foot shortages in the worst-hit countries.
The CEOs of 11 firms operating in west Africa -- including ArcelorMittal and Randgold -- said in a joint statement some measures were doing more harm than good.
"There is a risk the measures being taken to restrict travel to the countries most impacted by the virus will aggravate the growing humanitarian crisis," they said.
Despite the WHO's warning, the Liberian government said Monday it was lifting a quarantine on an Ebola hotspot near the country's international airport and announced it was moving its night-time curfew back two hours, from 9:00 pm to 11:00 pm.
The 17,000 residents of Dolo Town, 75 kilometres (47 miles) east of Monrovia, have been trapped since officials blockaded them in more than two weeks ago, amid an alarming spike in Ebola cases.
Meanwhile Sierra Leone announced plans to visit every home in the country of six million to track down people with Ebola and remove dead bodies.
Ebola, transmitted through bodily fluids, leads to haemorrhagic fever and -- in over half of cases -- death.
There is no specific treatment regime and no licensed vaccine.
Researchers reported in Nature Medicine on Monday however that a vaccine tested on monkeys had provided "complete short-term and partial long-term protection".
The study endorsed testing the vaccine on humans, with first results due by the end of the year.