The Internal Revenue Service may furlough employees in 2015 due to the drastic budget cuts it will face next year, according to the agency’s chief.

IRS Commissioner John Koskinen has already told staff of a hiring freeze and overtime suspension, with limited exceptions, in 2015. He told reporters Thursday the cuts forced upon the agency in the “CRomnibus” deal that set spending levels across federal government through September were so severe it could lead to intermittent shutdowns of the agency.

“People call it furloughs; I view it as: Are we going to have to shut the place down?” Koskinen said at a press conference. He added forcing employees to take unpaid days off was a last resort, but “there is no way right now we can say that won’t happen.”

Much like when IRS employees were forced to take three furlough days in the summer of 2013 due to sequestration cuts, Koskinen said the agency would shutter entirely for a day or two, or “whatever days it would take to close the gap that we can’t otherwise close in a reasonable way.”

He added final decisions about additional steps required by the agency will be made by IRS management -- in consultation with the National Treasury Employees Union -- in the coming weeks.

Congress appropriated IRS $10.9 billion for fiscal 2015, a $346 million reduction from fiscal 2014 and $1.5 billion less than President Obama requested in his budget proposal. Since 2010, the IRS budget has been slashed by $1.2 billion, or 10 percent. The agency has reduced its workforce by a staggering 13,000 employees in that period, and that number is likely to climb next year.

NTEU National President Colleen Kelley said the IRS budget is at its lowest point since 2007, “despite many more taxpayers and increased responsibilities,” such as enforcement of key Affordable Care Act provisions.

“I am very concerned about the impact that IRS budget cuts will have on the workforce and the agency’s mission,” Kelley said. “We will do everything we can to prevent these draconian cuts from resulting in hardship to frontline employees who provide vital services to taxpayers. Starving the IRS hurts more than just the agency’s workforce, it hurts all taxpayers.”

Koskinen said the slashed appropriations represent a “tax cut to tax cheats.”

“To the extent we have fewer people to audit and enforce the tax code,” he said, “that means some people cutting corners on their taxes or not complying are going to get away with it, and that is a decision that Congress has made.”

An email to IRS employees Wednesday afternoon said due to the cuts and $250 million in added expenses to pay for the anticipated 1 percent pay raise federal civilians are scheduled to receive next year, the agency will freeze hiring except in a few “mission-critical” areas, trim “limited travel even further” and stop overtime except in “critical” situations.

“We will review all contracts and other places where we can possibly realize further savings,” Koskinen wrote in the email. “And I have asked the heads of our organizational divisions to look for ways to cut their operating budgets during the next nine months. But I have made it clear that we will do our best not to take actions that make your job more difficult or less satisfying.”

Despite the cuts, Koskinen told employees their work was still appreciated.

“I have faith in your commitment to the nation and your dedication to serving taxpayers,” he wrote. “As always, I know you and your colleagues will do your best with the limited resources available to protect the integrity of the filing season, to enforce the tax code and to help taxpayers trying to meet their obligations. I will continue to highlight your work and our concern about the effect of these budget reductions.”