Sierra Leone President Ernest Bai Koroma asked the country to begin a week of fasting and prayers on Thursday to end the Ebola virus that has killed more than 2,700 of his countrymen.

The worst outbreak on record of the virus is still spreading in West Africa, especially in Sierra Leone, and the number of known cases globally has exceeded 20,000, the World Health Organization said on Wednesday.

In a New Year's Day broadcast, Koroma said the seven days of prayers and fasting would begin immediately. "Today I ask all to commit our actions to the grace, mercy and protection of God Almighty," he said.