Peter Strzok, a former FBI agent who became a political flashpoint after anti-Trump text messages of his became public, is suing the Justice Department and the FBI over his firing.

The lawsuit, filed Tuesday, alleges that the government caved to "unrelenting pressure" from Trump to fire him and argues that the dismissal violated his constitutional rights.

Strzok accused the agencies of violating his First Amendment rights of free speech and then denying him due process – protected by the Fifth Amendment – to challenge the dismissal. The lawsuit also argues that the DOJ's decision to give the text messages in question to reporters before sharing them with Congress was a violation of the Privacy Act.

Strzok became a target of those critical of the FBI's investigation into Russian interference in the 2016 election, including President Donald Trump, who has frequently lambasted Strzok and the investigation.

Anti-Trump texts between Strzok and FBI lawyer Lisa Page were made public in December 2017. The texts were sharply critical of Trump during his run for president. They were found by the Justice Department's internal watchdog during an investigation into the bureau's probe of Hillary Clinton's use of a private email server.

Strzok, a career counterintelligence agent, helped lead investigations into Clinton's emails and Russia's actions during the election. He was removed from former special counsel Robert Mueller's team after the texts came to light, and he was fired from the FBI in August.

The Justice Department's inspector general criticized Strzok and Page for writing the messages, which were sent on FBI phones, but it did not find that the Clinton email probe was affected by political bias.

Conservatives have held up the messages as evidence that the Clinton investigation was compromised and that the Russia investigation, which concluded earlier this year, was a politically motivated attack on Trump.

Strzok's lawsuit alleges that Trump's frequent public attacks led to his firing. The agency's move was "the result of unrelenting pressure from President Trump and his political allies in Congress and the media," it says, and notes that the FBI deputy director fired Strzok over the recommendation from the FBI's Office of Professional Responsibility.

The lawsuit also says that the government discriminated against Strzok's views because other employees who have supported Trump in the workplace have kept their job. It references the fact that the White House has not fired counselor Kellyanne Conway despite findings that she violated the Hatch Act – a law that restricts political activity by federal officials – by criticizing Democratic presidential candidates.

