As government shutdown approaches, agencies tell workers that furloughs are coming

Government agencies began warning their workers Thursday that they are preparing for a government shutdown -- and that they might have to go without pay.

Lawmakers have until the end of the day Sept. 30 to reach a deal to fund the federal government. If Congress doesn't act, the government will shut down at 12:01 a.m. ET on Sunday -- a situation that appears increasingly likely.

On Wednesday, the Office of Management and Budget gave the agencies the official heads up of a looming shutdown, according to two officials.

Then on Thursday, the top officials at each agency began sending out official notices to their workforce.

The Department of Homeland Security, a federal agency created in the aftermath of 9/11 terror attacks, told workers Thursday that it's preparing for a shutdown, but didn't say how long it expects the shutdown to last.

In a memo obtained by ABC News, a senior official told the workforce that "prudent management" requires that DHS prepare for the possibility that a lapse in funding could occur.

"While certain government activities must cease during a lapse, many DHS functions will continue to operate," wrote R.D. Alles, deputy undersecretary for management at DHS.

"During this time, some of you will be temporarily furloughed while others who perform excepted functions will continue to execute your assigned duties," he wrote.

At the Department of Veterans Affairs, employees were told that much of their work would be paid for with money already passed by Congress, including relying on leftover funds.

Of the 440,437 employees, only 15,620 were at risk of being furloughed if those funds ran out.

Payments from Social Security, Medicare and Medicaid, as well as health benefits for service members and veterans are not expected to be impacted by the shutdown because of their status as "mandatory" programs.

Many employees were told to wait for further instructions on whether they will be furloughed or required to come to work without pay.

According to one administration official, workers would likely learn of their status on Friday as to whether they would be expected to come to work on Monday. Official notification would happen later.

The union for the United States Capitol Police warned its members that it believes the shutdown could last two to four weeks. The union note tells personnel to await an email and mailed letter advising them of their work status.

The Capitol Police, which protect members of Congress, as well as other law enforcement agencies are considered "excepted" services and would still report to work during a shutdown. They would receive back pay once the spending deal is passed. Other federal employees are furloughed and sent home without pay.

All federal workers would receive back pay once the spending deal is passed, although union officials say it's not a good solution. In the last shutdown in 2018, many essential employees called in sick because they struggled to pay for child care, gas and other expenses to come to work.

As many as 4 million workers could lose pay as a result of a shutdown -- about half of whom are military troops and personnel.