The American strategy on Ebola is two-pronged: Step up desperately needed aid to West Africa and, in an unusual step, train U.S. doctors and nurses for volunteer duty in the outbreak zone. At home, the goal is to speed up medical research and put hospitals on alert should an infected traveler arrive.

With growing criticism that the world still is not acting fast enough against the surging Ebola epidemic, President Barack Obama has called the outbreak a national security priority.

Obama is to travel to Atlanta on Tuesday to address the Ebola crisis during a visit to the Centers for Disease Control and Prevention, the White House said. During his visit, Obama is to be briefed about the outbreak and discuss the U.S. response with officials.

The administration hasn't said how big a role the military ultimately will play - and it's not clear how quickly additional promised help will arrive in West Africa.

"This is also not everything we can and should be doing," Sen. Chris Coons, D-Del., who chairs a Foreign Relations subcommittee that oversees African issues, told the Senate last week.

He called for expanded military efforts and for Obama to appoint someone to coordinate the entire government's Ebola response.

"I've heard from organizations that have worked to transport donated supplies and can fill cargo plane after cargo plane but are having difficulty getting it all to West Africa," Coons added, urging government assistance.

Supplies aren't the greatest need: "Trained health professionals for these Ebola treatment units is a critical shortage," said Dr. Steve Monroe of the Centers for Disease Control and Prevention, or CDC.

Aiming to spur them, the CDC is beginning to train volunteer health workers headed for West Africa on how to stay safe, Monroe said. CDC sent its own staff to learn from Doctors Without Borders, which has the most experience in Ebola outbreaks. CDC will offer the course at a facility in Anniston, Alabama, for the next few months, teaching infection-control and self-protection and letting volunteers - expected to be mostly from nongovernment aid groups - practice patient triage.

"It's gone beyond an Ebola crisis to a humanitarian crisis. It does require more of a U.S. government-wide response, more than just CDC," Monroe said.

Here are some questions and answers about that response:

Q: What is the U.S. contributing?

A: The U.S. government has spent more than $100 million so far, said Ned Price of the National Security Council. Last week, the U.S. Agency for International Development announced it would spend up to $75 million more to provide 1,000 treatment beds in Liberia, the worst-hit country, and 130,000 protective suits for health workers.

The Obama administration has asked Congress for another $88 million to send additional supplies and public health experts, and to develop potential Ebola medications and vaccines.

Also, the State Department has signed a six-month contract, estimated at up to $4.9 million, for a Georgia-based air ambulance to be on call to evacuate any Ebola-infected government employees, and other U.S. aid workers when possible.

"The ability to evacuate patients infected with the Ebola virus is a critical capability," said Dr. William Walters, the State Department's director of operational medicine.

Q: Beyond delivering supplies, what's happening on the ground?

A: The CDC currently has 103 staffers in West Africa working on outbreak control and plans to send about 50 more. They help to track contacts of Ebola patients, train local health workers in infection control and help airport authorities screen whether anyone at high risk of Ebola is attempting to leave.

Two of the CDC workers are in Ivory Coast to try to stay ahead of the virus, helping health authorities prepare in case an Ebola patient crosses the border into that country.

Q: What are the U.S. military's plans?

A: The Defense Department has provided more than 10,000 Ebola test kits to the region and plans to set up a 25-bed field hospital in the Liberian capital for infected health care workers.

Pentagon spokesman John Kirby suggested Friday that more could be coming.

"The Department of Defense has capabilities that might prove helpful," he said, adding, "We're having those discussions right now."

Q: Will Ebola come here?

A: U.S. health officials are preparing in case an individual traveler arrives unknowingly infected but say they're confident there won't be an outbreak here.

People boarding planes in the outbreak zone are checked for fever, but symptoms can begin up to 21 days after exposure. Ebola isn't contagious until symptoms begin, and it takes close contact with bodily fluids to spread.

Q: Where would sick travelers be treated? The U.S. only has four of those isolation units where Ebola-stricken aid workers were treated.

A: "There's still a perception in the public that the only place these people can be treated is at one of these specialized facilities like the one at Emory or Nebraska, and that's just not the case," Monroe said. "We are confident that any hospital in the U.S. can care for" an Ebola patient.

After all, five U.S. cases of similar hemorrhagic viruses - one Marburg virus, the others Lassa fever - have been treated in the past decade.

The CDC is telling hospitals to ask about travel if someone has suspicious symptoms, to put the person in a private room with a separate bathroom while asking CDC about testing and to wear a gown, mask and eye protection when delivering care.

"This virus is completely inactivated by all the normal disinfectants used in a hospital setting," Monroe noted.