Thousands of probationary federal health agency workers fired by letter this weekend. Here's what it said.

Probationary workers across multiple federal health agencies in the Department of Health and Human Services received virtually identical letters Saturday evening informing them they would be terminated from their positions, sources told CBS News. 

"Unfortunately, the Agency finds that you are not fit for continued employment because your ability, knowledge and skills do not fit the Agency's current needs, and your performance has not been adequate to justify further employment at the Agency," read the letter obtained by CBS News.

The letter was signed by Jeffrey Anoka, acting head of human resources for the Department of Health and Human Services. One health official told CBS News thousands of letters were sent out Saturday.