Veterans Affairs officials issued guidance Thursday exempting more than 300,000 department health care posts from the White House's federal hiring freeze, labeling them as essential to public health and department operations.

The VA memo exempts roughly three-quarters of the Veterans Health Administration's roughly 400,000-employee workforce.

VA hires about 40,000 new workers every year to maintain operations at VA medical sites. It's unclear if that can continue under Trump's hiring halt.

VA officials said the exemptions to a Jan. 20 executive order are necessary to provide health care and services to veterans.