U.S. congratulates Liberia on eliminating Ebola: White House

The U.S. government on Saturday congratulated Liberia for the end of the Ebola outbreak in the West African country.

Earlier in the day, the World Health Organization declared Liberia free of the Ebola virus, as the country has had no new cases in 42 days.

The WHO said in a statement that the interruption of transmission is a monumental achievement for a country that reported the highest number of deaths in the largest, longest, and most complex outbreak since Ebola first emerged in 1976.

At the peak of transmission, which occurred during August and September 2014, the country was reporting from 300 to 400 new cases every week.

Saturday marks 42 days since Liberia's last Ebola case -- the benchmark used to declare the outbreak over because it represents two incubation periods of 21 days for new cases to emerge.

"We congratulate the people of Liberia on reaching this important marker," the White House said in a statement.

The White House, however, urged continued vigilance because the Ebola outbreak still persisted in neighboring Sierra Leone and Guinea. "We must not let down our guard until the entire region reaches and stays at zero Ebola cases," the statement said.

The virus has killed more than 11,000 people so far across the three countries. Endite