() The Internal Revenue Service is expecting to terminate more than 3,500 employees who work in the small business/self-employed division.

CBS News first reported the expected firings, which were announced to managers in the division Wednesday.

The terminations are expected to affect probationary hires who are “not deemed as critical to filing season.” The division helps small businesses and entrepreneurs comply with taxes and assists with debt relief, serving 57 million Americans.

The IRS is experiencing some of the largest numbers of mass firings at an agency across departments even as the peak tax season, which goes from mid-March through mid-April, approaches.

Another division, which handles large business and international issues, also received an email requesting managers come into the office Thursday to discuss firings but did not say how many people would lose their jobs.

The IRS employs tens of thousands of people and the firings come as the Trump administration has worked to terminate probationary hires across federal agencies.

In some cases, the firings have led agencies to scramble to try to get people back as people in critical roles, including those who safeguard the nation’s nuclear weapons and those who play a role in preventing a bird flu pandemic, were fired in mass terminations.

The Department of Government Efficiency, headed by billionaire Elon Musk, has been working to access information in federal agencies, including an internal data system at the IRS that has Americans’ individual tax information.