Ontario Liberal MP Celina Caesar-Chavannes announced Saturday she would not be seeking re-election this year.

In a statement posted to Twitter, the member for Whitby, Ont., explained she had informed the prime minister and party whip of her "tremendously difficult" decision on Feb. 12.

She also stressed that her choice wasn't related to the ongoing SNC-Lavalin affair and the testimony of her caucus colleague Jody Wilson-Raybould, who this week described interference by the prime minister and high-level government officials over her decision not to offer a deferred prosecution deal to the Quebec company.

She added she had immense respect for the former justice minister and attorney general and that would never change. The MP had commented several times on Twitter in support of Wilson-Raybould during the unfolding events surrounding her resignation from cabinet.

"Factors influencing this decision started long before Feb.12," the statement says. "It is a personal decision, based on a number of factors."

Caesar-Chavannes said her mind had been made up for months, dating back to before she decided not to continue as a parliamentary secretary in September.

Thank you Whitby and to the <a href="https://twitter.com/hashtag/HereForCelina?src=hash&ref_src=twsrc%5Etfw">#HereForCelina</a> family. Please see my statement below: <a href="https://t.co/VFN7omm7eU">pic.twitter.com/VFN7omm7eU</a> —@MPCelina

She thanked her colleagues on both sides of the aisle for continuing to "fight the good fight" for Canadians.

Understanding some might be upset by her decision to step back from federal politics, she encouraged others —especially those who feel underrepresented — to run for public office.

"I will continue to push boundaries, dismantle the status quo and break glass ceilings, and I hope you will expect no less from me."

Caesar-Chavannes had been a strong advocate for fighting the stigma around mental health. She was open about her own struggles with depression.

To my dear friend <a href="https://twitter.com/MPCelina?ref_src=twsrc%5Etfw">@MPCelina</a>... Tim & I have read your words-w/ sadness-but respecting your decision. You are an extraordinary individual—a crusader for equality, justice & inclusion. I know your drive will not change in whatever adventure you next choose. With deep respect C3! 🙏🏽 <a href="https://t.co/C3dZmYBbhH">https://t.co/C3dZmYBbhH</a> —@Puglaas

Twitter stand-off with Maxime Bernier

She also was known for calling out people for offensive remarks, including now-leader of the People's Party of Canada Maxime Bernier.

For months, the two were locked in a social media battle about identity politics.

In the spring of 2018, Bernier tweeted that Caesar-Chavannes believes "the world revolves around" her "skin colour." That was in response to Caesar-Chavannes chiding him in an interview with the Globe and Mail.

The feud began in March, when Bernier criticized the Liberal government's promotion of funding for "racialized Canadians" and said he thought the goal of anti-racism policy was to create a "colour-blind" society.

Caesar-Chavannes fired back, suggesting Bernier "do some research ... as to why stating colour blindness as a defence actually contributes to racism."

"Please check your privilege and be quiet," she added — provoking Bernier to invoke "free speech."

Elected in 2015, she served as the parliamentary secretary to the prime minister and to the minister of international development.

She joins Mark Eyking, Bill Casey, Colin Fraser, TJ Harvey and Scott Brison on the list of Liberal MPs choosing not to run again in October's general election.