ATLANTA >> Calling the Ebola outbreak in West Africa a potential threat to global security, President Barack Obama is ordering 3,000 U.S. military personnel to the stricken region amid worries that both the financial and human cost of the outbreak is spiraling out of control.

Obama also called on other countries to quickly supply more helpers, supplies and money.

“If the outbreak is not stopped now, we could be looking at hundreds of thousands of people affected, with profound economic, political and security implications for all of us,” Obama said Tuesday after briefings at the Centers for Disease Control and Prevention.

“It’s a potential threat to global security if these countries break down,” Obama said, speaking of the hardest-hit countries of Liberia, Sierra Leone and Guinea. At least 2,400 people have died, with Liberia bearing the brunt.

Obama outlined a series of new steps by the U.S. to help contain the outbreak, which he said is getting worse. The steps include sending military personnel, training health care workers and erecting health care facilities in Liberia.

He described the task ahead as “daunting” but said what gives him hope is that “the world knows how to fight this disease.”

Obama announced that Maj. Gen. Darryl Williams, head of U.S. Army Africa, will head a military command center based in Liberia.

White House press secretary Josh Earnest said the 3,000 troops would not provide direct care to Ebola patients. A substantial number will be stationed at an intermediate base in Senegal, Earnest said, with others at locations in Liberia.

The U.S. effort will include medics and corpsmen for treatment and training, engineers to help erect the treatment facilities and specialists in logistics to assist in patient transportation.

The World Health Organization warned that the number of Ebola cases in West Africa could start doubling every three weeks and that the crisis could end up costing nearly $1 billion to contain. Joanne Liu, president of Doctors Without Borders, said the global response was falling short. “The window of opportunity to contain this outbreak is closing,” Liu told a meeting Tuesday at the United Nations in Geneva.

Nearly 5,000 people have become ill from Ebola in Liberia, Sierra Leone, Guinea, Nigeria and Senegal since it was first recognized in March. WHO says it anticipates that figure could rise to more than 20,000.

With the addition of military personnel, administration officials said that the new U.S. initiatives aim to:

–Train as many as 500 health care workers a week.

–Erect 17 heath care facilities in Liberia of 100 beds each.

–Set up a joint command headquartered in Monrovia, Liberia, to coordinate U.S. and international relief efforts.

–Provide home health care kits to hundreds of thousands, including 50,000 that the U.S. Agency for International Development will deliver to Liberia this week.

–Carry out a home- and community-based campaign to train local populations on handling exposed patients.

Meanwhile, a Senate panel held a hearing on the outbreak in Washington. Expected to testify were Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, and Dr. Kent Brantly, an American physician who contracted Ebola while working in Liberia but recovered after treatment with an experimental drug. Obama met with Brantly at the White House on Tuesday before departing for Atlanta.

At the hearing, Sen. Tom Harkin, D-Iowa, declared, “This outbreak has spread in ways that are potentially catastrophic for the world.”

Sen. Lamar Alexander, R-Tenn., said urgent action was needed. “We must take the dangerous, deadly threat of the Ebola epidemic as seriously as we take ISIS,” he said, referring to the extremist group in Syria and Iraq.

Separately, House Speaker John Boehner, R-Ohio, said, “Frankly, I’m a bit surprised the administration hasn’t acted more quickly to address what is a serious threat, not just to Africa but to others across the world.” He predicted action “in the coming weeks” by the executive and legislative branches of government “to look at how do we best contain this very horrible disease.”

Obama administration officials said money for the stepped-up effort to combat the disease would come from $500 million in overseas contingency operations, such as the war in Afghanistan, that the Pentagon already has asked Congress to redirect to carry out humanitarian efforts in Iraq and in West Africa. Officials said it would take about two weeks to get U.S. forces on the ground.

Ebola is spread through direct contact with the bodily fluids of sick patients, making doctors and nurses especially vulnerable to contracting the virus, which has no vaccine or approved treatment.

Obama’s trip came a day after the United States also demanded a stepped-up international response to the outbreak. The U.S. ambassador to the United Nations, Samantha Power, called Monday for an emergency meeting of the U.N. Security Council on Thursday, warning that the potential risk of the virus could “set the countries of West Africa back a generation.”

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Associated Press writers Edith M. Lederer at the United Nations and Erica Werner in Washington contributed to this report.