There was no proof or elaboration on the claim.

The Food and Drug Administration is an agency within the Department of Health and Human Services, part of the executive branch. The head of the FDA, Stephen Hahn, was nominated by Trump on November 5, 2019.

At the time of his tweet, the United States totaled 5,861,632 cases and suffered 180,202 deaths.

Trump has referred to the “deep state” in the past, including the “Deep State Department,” prompting Dr. Anthony Fauci to struggle in holding his laughter.

Reuters – Trump says without proof that FDA ‘deep state’ slowing COVID trials
The Hill – Democrats tear into Trump’s ‘deep state’ tweet: His ‘lies and recklessness’ have ‘killed people’
Wikipedia – Food and Drug Administration
Wikipedia – Commissioner of Food and Drugs
Worldometer – Coronavirus, United States