MONROVIA, Liberia - Liberia President Ellen Johnson Sirleaf has closed some border crossings and ordered strict quarantines of communities affected by the Ebola outbreak.

The announcement late Sunday came a day after Sirleaf formed a new taskforce charged with containing the disease, which has killed 129 people in the country and more than 670 across the region.

A top Liberian doctor died of Ebola over the weekend, and two American aid workers have fallen ill.

Last week a Liberian official boarded an international flight to Nigeria and died of the disease in a Lagos hospital. Ebola is spread through contact with bodily fluids.

Sirleaf said all entry points except for the international airport outside Monrovia and "key border crossings" would be closed, and new inspection procedures would be strictly observed.