The Internal Revenue Service launched a sweeping round of layoffs on Friday, beginning with the closure of its Office of Civil Rights and Compliance, according to an internal email obtained by ABC News.

The move marks the start of a broader workforce reduction that is expected to impact nearly 25% of the agency’s staff, sources familiar with the plan said. The IRS, which employs roughly 100,000 people, had previously outlined plans to cut 18% to 20% of its workforce by mid-May.

The email to employees described the restructuring as part of an effort to “increase the efficiency and effectiveness of the IRS in accordance with agency priorities,” and said the cuts would affect “multiple offices and job categories.” Staff remaining in the now-defunct civil rights office will be reassigned to the Office of Chief Counsel.

Layoffs will roll out in phases, and the IRS plans to offer early retirement incentives starting next week. The email also confirmed broader staffing changes across departments, indicating a significant shift in the agency’s operational structure.

Adding to the shakeup, approximately 50 IT security employees were recently placed on administrative leave, according to sources. The IRS is facing mounting pressure to streamline its workforce and accommodate growing demands for interagency data sharing—even during the peak of tax season.

The Trump administration has asserted that the cuts won’t affect core tax return processing staff. Still, tax experts and former officials are raising red flags.

“For decades, it’s been a rule of thumb: never disrupt staffing during filing season—it’s too sensitive,” a former IRS commissioner told ABC News. “Laying off nearly 10% of the IRS in the middle of it? That’s a dangerous gamble.”

Earlier this year, over 4,000 employees accepted voluntary departure offers from the administration, while more than 6,600 probationary employees were terminated—though many have since been reinstated following legal challenges. It remains unclear if these same groups will be included in the latest reduction efforts.

Since January, the IRS has seen a wave of leadership turnover, including the departures or demotions of the acting commissioner, chief human resources officer, and acting general counsel.

Neither the IRS nor the White House responded to ABC News’ request for comment.