The Ebola epidemic in West Africa has killed more than 2,100 people, making it the biggest outbreak ever, and the World Health Organization (WHO) warns it's just the start.

WHO is predicting thousands of new cases in the coming weeks, according to a recent report. The organization predicted the outbreak will take six to nine months to contain and may infect up to 20,000 more people.

At least 40 percent of the cases have been in just the last three weeks, the UN health agency said, adding that "the outbreak accelerated faster than expected".

"The cases are increasing. I wish I did not have to say this, but it is going to get worse before it gets better," Tom Frieden, the director of the Center for Disease Control and Prevention, told a news conference in Monrovia last Wednesday.

The Pentagon is sending a 25-bed field hospital to Liberia to help treat health workers who have contracted Ebola there. The WHO is asking governments to triple current aid efforts to battle the explosive outbreak.

The $22 million hospital is being provided at the request of the U.S. Agency for International Development, which is coordinating the U.S. response to the Ebola outbreak first identified in Guinea in March.

The announcement came after President Barack Obama said on Sunday that the United States must do more to help control the outbreak to stop it from becoming a global crisis that might eventually threaten Americans.

"If we don't make that effort now, and this spreads not just through Africa but other parts of the world, there's the prospect then that the virus mutates, it becomes more easily transmittable," Obama said in an interview with NBC's Meet the Press. "And then it could be a serious danger to the United States."

Meanwhile in Nebraska, Dr. Rick Sacra, the third American missionary to be infected with the Ebola virus, remains in stable condition.

Doctors in Nebraska say they're comparing notes with Emory Hospital in Atlanta, which already treated two Americans with Ebola.

"It's virtually the same strain. I've been on the phone to Emory people every day," Dr. Phil Smith, medical director of the Omaha unit, said.

Federal officials say they sent Sacra to Omaha instead of Atlanta to prepare other isolation units in the United States to take more Ebola patients if needed.

The virus has now spread to five countries in West Africa. Governments are doing everything they can to contain the disease, from imposing night-time curfews to ordering multi-day countrywide lockdowns.

According to the Christian Broadcast Network, Churches and Non-profit agencies like Operation Blessing are also stepping up efforts.

Operation Blessing's David Darg told CBN News that churches in Liberia are working to encourage prevention.

"We have Ebola prevention teams - church volunteers that are going out into the communities - warning people of the signs, telling people what to do if they have symptoms," Darg said.

Liberia is the country worst hit by the virus and it suffers from the greatest shortage of doctors, according to aid workers there.