The official was dismissed just days before his planned retirement on Sunday and two days before his 50th birthday, Fox News reported.
"I am being singled out and treated this way because of the role I played, the actions I took, and the events I witnessed in the aftermath of the firing of James Comey," McCabe said.
McCabe has said he considered his firing was because he supported former FBI Director James Comey's claim that Trump tried to urge him into killing a probe into Russian interference in the 2016 US election. Comey has told Congress he saved a detailed written record of his conversations with Trump.
Twitter has exploded after McCabe's dismissal.
READ MORE: US Attorney General: McCabe Firing From FBI Is 'Effective Immediately'
McCabe has long been a game of Trump's anger. His dismissal precedes the release of an inspector general report that's supposed to conclude that McCabe was not forthcoming about topics related to the FBI investigation of Hillary Clinton's emails.