GENEVA - The World Health Organization (WHO) on Thursday declared Liberia free of Ebola virus transmission in the human population.

The WHO said in a statement that Liberia's ability to effectively respond to the Ebola outbreak is due to intensified vigilance and rapid response by the government and multiple partners. Liberia now enters a 90-day period of heightened surveillance.

In Liberia, transmission had been declared over on May 9, but the disease re-emerged on June 29 and six additional cases were identified.

Under the leadership of the Liberian government, an effective response was rapidly initiated to contain the new outbreak.

Members of the community were engaged and effectively contributed to contact tracing and social mobilization. International partners supported the government in areas such as technical assistance, provision of personnel, food, supplies and equipment.

The WHO commended the government of Liberia and its people for the successful response to this recent re-emergence. It is in full accord with government calls for sustained vigilance and will continue to support the country during the 90 days of heightened surveillance and in its early recovery efforts.

According to WHO's latest Ebola situation reports, there were three confirmed Ebola cases reported last week in Guinea, and Sierra Leone found a new case over the past two weeks.

As of August 30, there have been a total of 28,073 reported confirmed, probable, and suspected cases of Ebola in Guinea, Liberia, and Sierra Leone, with 11,290 reported deaths.