Newly revealed documents appear to indicate that several high-level officials within the Food and Drug Administration (FDA) resigned from their positions out of protest of the Centers for Disease Control’s (CDC) efforts to rush the COVID-19 vaccines into production and distribution.

As reported by the Daily Caller, one such official was Dr. Phil Krause, the former deputy director of the FDA’s vaccine review office, who submitted his resignation last year.

In official emails, obtained via a Freedom of Information Act (FOIA) request by the watchdog group Judicial Watch, Krause and Dr. Marion Gruber, director of the FDA’s vaccine review office, both expressed their concerns about quickly authorizing COVID-19 boosters for the general population without proper testing.