FREETOWN (AFP) - The Sierra Leone government on Wednesday declared a five-day lockdown in the country's north to step up efforts to contain the Ebola epidemic, while making an exception for Christmas.

"Muslims and Christians are not allowed to hold services in mosques and churches throughout the lockdown except for Christians on Christmas Day (Thursday)," Alie Kamara, resident minister for the Northern Region, told AFP.

The lockdown is designed "to intensify the containment of the Ebola virus," he said, adding: "We are working to break the chain of transmission."

Deputy communication minister Theo Nicol said "the lockdown for five days... is meant for us to get an accurate picture of the situation," adding: "Other districts will carry on with their own individual lockdown after this if they deemed it necessary."

Ebola has killed more than 7,500 people, almost all of them in west Africa. Sierra Leone, Liberia and Guinea are the three countries worst-hit by the epidemic.

Sierra Leone overtook Liberia recently as the country with the highest number of Ebola infections.

Kamara said shops and markets would be closed throughout the period, and "no unauthorised vehicles or motorcycle taxis" would be allowed to circulate "except those officially assigned to Ebola-related assignments."

Among "key objectives" is to allow health workers to identify patients, Kamara said.