Former FBI director James Comey on Sunday tweeted that he hopes 2018 "brings more ethical leadership," a post surely to be intended as a dig toward President Donald Trump.

Here's hoping 2018 brings more ethical leadership, focused on the truth and lasting values. Happy New Year, everybody. — James Comey (@Comey) December 31, 2017

Trump fired Comey in May while he was spearheading the Russia investigation, and on Christmas Eve, the president ripped into him for being a leaker after Comey told the Senate Intelligence Committee that he had shown a memo documenting his private conversation with Trump to a friend at Columbia Law School.

"How can FBI Deputy Director Andrew McCabe, the man in charge, along with leakin' James Comey, of the Phony Hillary Clinton investigation (including her 33,000 illegally deleted emails) be given $700,000 for wife's campaign by Clinton Puppets during investigation?" Trump tweeted.

Comey also said the president pressured him to drop his investigation into former national security adviser Michael Flynn when both were still employed, information that some outlets say Special Counsel Robert Mueller is using to build a case against Trump for obstructing an FBI investigation.

Comey has tweeted often since his firing, often in relation to news of the day.

Sadly, we are now at a point in our political life when anyone can be attacked for partisan gain. James Baker, who is stepping down as FBI General Counsel, served our country incredibly well for 25 years & deserves better. He is what we should all want our public servants to be. — James Comey (@Comey) December 23, 2017