At an emergency meeting due on Thursday, the UN Security Council will try to find ways to scale up the global response to the Ebola epidemic.
"It is crucial that council members discuss the status of the epidemic, confer on a coordinated international response and begin the process of marshalling our collective resources to stop the spread of the disease," US Ambassador Samantha Power said Monday.
The worst-ever outbreak of the deadly virus has killed more than 2,400 people in West Africa, with Liberia the region's hardest-hit country.
The UN is appealing for $600 million for supplies as part of a massive surge of aid, with countries asked to send doctors, nurses, beds, trucks, equipment and other vehicles to the affected nations.
The world body has set a goal of stopping the spread of Ebola within six to nine months but aid agencies are complaining that help is slow in reaching those in need.
"Our collective response to date has not been sufficient," said Power, whose country holds the presidency of the 15-member council this month.
"The situation on the ground is dire and is growing worse by the day."
The US envoy did not specify what action the council was planning, but diplomats said a resolution was being prepared that could call for specific measures.
UN Secretary General Ban Ki-moon is planning a "high-level event" on the sidelines of the UN General Assembly that opens next week to draw attention to the crisis and the need for action.
Liberian Defense Minister Brownie Samukai told the council last week that the outbreak posed "a serious threat" to his country's existence and that it was "spreading like wildfire, devouring everything in its path."
The tropical virus can fell its victims within days, causing severe fever and muscle pain, weakness, vomiting and diarrhea -- in some cases shutting down organs and causing unstoppable bleeding.
No widely available vaccine or treatment exists but health experts are looking at fast-tracking two potential vaccines and eight treatments, including the drug ZMapp.