Washington CNN  — 

The Transportation Security Administration is making a plea for 250 people to bolster its workforce of backup officers, the latest sign the agency is straining under the pressure of the shutdown, according to an internal email sent Monday morning from a TSA executive and obtained exclusively by CNN.

The email, sent to TSA officials in more than 10 states with more than 100 airports, asks for employees to move from their home airports to those airports struggling with low staffing, an indication the agency is bracing for even more callouts.

The email is the latest example of increasing anxiety within TSA about the rising number of callouts as employees prepare to miss a second paycheck this week. Ten percent of TSA’s workforce had unexcused absences on Sunday, the agency said.

This is the second such request for more backup screeners to help fill staffing gaps, according to the email and a TSA official familiar with its contents.

All members of the agency’s National Deployment team, a rapid response team comprising of TSA officers can be sent to airports across the country to help fill the staffing gaps, have already been dispatched, according to the email. The team has been used to patch up gaps at airports in Atlanta, New York, Chicago and elsewhere as the partial government shutdown extends into its fifth week.

The Atlanta airport, already the world’s busiest, is preparing for an influx of travelers in just under two weeks when the city hosts the Super Bowl.

The deployment team fluctuates in size based on the conditions and needs, said TSA spokesman Jim Gregory.

“We are working every day to ensure our checkpoints are fully covered nationwide and always are welcoming new volunteers,” Gregory said, noting the employees would not be paid until the end of the shutdown. “Our workforce is incredibly mission-focused, and we have had hundreds answer the call.”

The volunteers would presumably come from airports that haven’t faced strain from callouts in order to help airports that have.

A similar request made last week netted the agency at least 160 volunteers, the email said.

In another sign of how badly volunteers are needed, the email reminds TSA officials the agency would pick up the cost of their hotel and travel. According to the email, officers will use their government-issued credit cards for meals and incidentals, but those credit card payments would not have to be made until the government reopens.

Gregory said the agency is working to reduce the need to close security checkpoints and lanes but acknowledges more could close as the government shutdown continues.

“In coordination with the airlines and airport authorities, our federal security directors will implement contingency plans as necessary, which could mean lane closures. We have seen very few lane closures across the nation so far,” he said.

The number of TSA officers calling out from work has grown in recent days.

After callouts hit 10% on Sunday nationwide, according to TSA, 7.5% of employees called out Monday, compared to 3.3% on the same Monday a year ago.

“Many employees are reporting that they are not able to report to work due to financial limitations,” TSA said in a statement.

In early January, CNN first reported that hundreds of TSA officers had called out from work, raising concerns among union officials and screeners that the security of air travel would be negatively impacted.

One regional TSA manager told screeners at Palm Springs International Airport, a small airport in California, that excessive absences have “adversely impacted security operations” at the airport, and warned of “disciplinary action” for employees who miss work.