Some 6 million residents in Sierra Leone hunkered down at home on Friday as the country began a three-day lockdown aimed at raising awareness about the deadly Ebola virus.

The normally crowded streets were empty in the hilly capital, Freetown, with only security officials and essential workers with government passes allowed out. "Freetown is looking very lonely. We are all just staying at home waiting," said taxi driver Salifu Conte.

The dramatic measures came as the United Nations said the outbreak, which has infected some 5,300 people largely in Sierra Leone, Guinea and Liberia, was a threat to world peace. Health workers have struggled to stem the spiralling numbers as residents in rural areas have fled or attacked them. On Thursday, nine members of an education team in Guinea were found with slit throats after panicked residents thought they had come to attack them.

Almost 30,000 volunteers have been trained to hand out soap and raise awareness in the campaign known locally as "hose to hose tok" (house-to-house talk), but there were delays across the capital. "We volunteers have been waiting since 7am, but the health officials haven't come yet. We're ready to go, we want this Ebola to end, but the planning has not been the best," said Ade Kamara in Freetown.

Elsewhere teams of four began to fan out across the country, where they are expected to reach around 1.5m houses by Sunday.

In Kailahun, the eastern region hardest-hit by the outbreak, health worker Vandy Cawray prepared to be cut off for three days as he headed to remote villages he believes may not yet have received any education on the outbreak. Villagers in the northern district of Mayera vanished when education workers arrived to greet them on Thursday.

"It shows we still have work to do," Cawray said grimly. He shrugged off safety worries amid news of the team killed by residents in Womey, a Guinean village deep in the dense tropical forests that also spill into neighbouring Liberia.

"We have to do this properly. They've seen this terrible thing is happening and we need to help them," he said. Most people he had spoken to were more worried about lost earnings and feeding themselves, he said. "I tell them they just have to manage however they can, because we have to kick Ebola out."

Sierra Leone's president said if the population heeded the volunteers' advice, it would "help to reverse the increasing trend of the disease transmission and become a very big boost to our collective effort to stop the outbreak".

In a message broadcast on television and radio, Ernest Bai Koroma said: "These are extraordinary times and extraordinary times require extraordinary measures."

Others echoed that message. "This is an opportunity to hear from families what they want to know about Ebola," said Roeland Monasch, head of Unicef, which has helped train volunteers. "If people don't have access to the right information, we need to bring life-saving messages to them, where they live, at their doorsteps. The fight against Ebola needs to happen in every household, in every community and in every treatment centre."

But some health organisations worry the lockdown could drive already panicked communities into further isolation. Médecins sans Frontières also expressed concerns about where potential new cases would be treated.

"We're quite worried about the management of this campaign. Every single treatment centre in the country is full," said Christina Falconi, country coordinator for Sierra Leone.

Government officials said they expected to discover as many as 20% more new patients, who would then be taken to hospitals. But an official medic told the Guardian that a new surge could lead to confirmed cases and suspected cases being held together amid a lack of capacity. "It is a worry. There is a quite rigorous testing process before you can confirm the cases, and many of the early symptoms are the same as ordinary illnesses like malaria or food poisoning," the source said.

There are other worries. Hazel Chandler's organisation has turned its music and art studios into a temporary shelter for the street youth it normally trains. "A lot of them survive by sweeping or carrying things for people on the streets, so they've lost their hustle. Nobody seems to have made any plans for those people who don't actually have a home to be locked down in," said the director of Freetown-based WAYout.