(CNN/CBS4) — The Biden administration’s rollout out of active-duty troops to boost vaccination capacity is off to a slow start as the Federal Emergency Management Agency sorts through requests from individual states, according to multiple defense officials.

FEMA initially anticipated that as many as 10,000 troops would be used in the effort, but so far barely a tenth of that number have been authorized for deployment and there is little clarity on how many more will be used.

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At the end of last week, Defense Secretary Lloyd Austin approved 1,110 troops to help with vaccination efforts but only a fraction of that number have received orders. A team of 222 military personnel will head to a vaccination site in Los Angeles, a FEMA spokesperson said, adding that they will arrive on Thursday and be operational on or around Monday.

“Getting shots — vaccinations — in people’s arms is the mission,” said Lt. Gen. Laura J. Richardson, commander of Army North. “And this team, here on behalf of the governor and state, has the ability to get thousands more people vaccinated every day.”

(credit: U.S. Army Fort Carson)

The team is made up primarily of vaccinators, registered nurses and other medical personnel from Fort Carson in Colorado.

The Defense Department and FEMA are still discussing further deployments, but it’s now unclear how many from the agency’s initial proposal of 10,000 troops — or even the 1,110 already authorized — will ultimately take part in the effort to establish vaccination mega-sites. FEMA is leading the whole-of-government effort to boost vaccination numbers across the country.

“When the nation calls, we answer. The number one focus of the Army is to fight and win the nation’s wars and right now we’re at war with COVID. We’re taking the fight back to COVID by vaccinating as many people as we can and that’s what we’re looking forward to,” said Fort Carson 1st Lt. Benjamin Stricklin.

A FEMA spokesperson said the agency is working to fill all requests for federal personnel from states and localities based on the greatest need, but the spokesperson did not answer how many outstanding requests FEMA was currently handling. The agency has not publicly said what state requests it already has.

“FEMA is working to determine where the next teams are most needed based on requirements from the states, and DoD anticipates moving another 100 personnel in the coming days and hundreds more in the weeks following,” the spokesperson said.

Beyond the initial team earmarked for California, there is no indication when the balance of the 10,000 troops initially discussed could be brought into the effort, officials said.

The request was based on President Joe Biden’s initiative to raise vaccination levels to 1.5 million per day in his first 100 days in office. FEMA estimated that a deployment of 10,000 military personnel to potentially 100 vaccination mega-hubs around the country could facilitate nearly 500,000 additional vaccinations a day, though FEMA noted the buildup to those numbers would be “incremental.”

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Even though the administration has hit the 1.5 million number in recent days, the effort is still on.

“Nobody is talking about ending the effort,” said a defense official directly familiar with the planning.

(credit: CBS)

But the size and composition of different teams may change. Instead of the larger 222-person team headed to California, smaller military teams of 25 people each are being assembled to deploy to locations in New Jersey to meet state requests, according to a defense official. These personnel are not expected to come from the pool of 1,110, but rather another already existing allocation of troops earmarked to help with medical Covid-19 requirements.

The Pentagon is making clear that it is waiting for FEMA to tell it where the agency wants troops.

“DoD expects FEMA will be requesting additional DoD support as new sites for national vaccination centers are identified,” Pentagon spokesman Chris Mitchell told CNN.

Vaccine availability also poses limitations. The availability of vaccines informs the timing, location, and level of Defense Department support that FEMA requires, Mitchell said

The FEMA spokesperson said the “supply of vaccine is a factor for consideration; it is not a sole driving factor in mission success.”

Separately, the National Guard has 23,000 troops on duty providing vaccines as well as conducting testing and screening and other Covid-19-related assistance. The Army Corps of Engineers is working with FEMA on establishing community vaccination centers with walk-up, drive-thru, and mobile vaccination capability.

By Barbara Starr and Geneva Sands, CNN

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(© Copyright 2021 CBS Broadcasting Inc. All Rights Reserved. CNN contributed to this report.)