Trump encourages Rep. Julia Letlow to primary Sen. Bill Cassidy

President Donald Trump encouraged Rep. Julia Letlow, R-La., to primary Sen. Bill Cassidy, R-La., for his U.S. Senate seat in a post on Truth Social Saturday evening.

"Should she decide to enter this Race, Julia Letlow has my Complete and Total Endorsement. RUN, JULIA, RUN!!!" Trump wrote.

Letlow said in a social media post Saturday that she is "honored to have President Trump’s endorsement and trust. My mission is clear: to ensure the nation our children inherit is safer and stronger."

"This United States Senate seat belongs to the people of Louisiana, because we deserve conservative leadership that will not waver," she said.

In recent weeks, Letlow has told people around her that she was still considering running, but would only get into the race if Trump committed to endorsing her, according to two GOP sources familiar with the matter.

Asked by NBC News on Tuesday if she’s made up her mind, Letlow said, "I haven’t decided."

She declined to answer any follow up questions, including whether she wanted an endorsement from Trump before she entered the race.

Cassidy posted on social media Saturday, after Trump encouraged Letlow to run, that he is "proudly running for re-election as a principled conservative who gets things done for the people of Louisiana."

"If Congresswoman Letlow decides to run I am confident I will win," he said.

Cassidy told NBC News on Wednesday that "senior people" in the Trump administration told him the President would not endorse.

"I’m running for re-election. That’s all I can say," Cassidy said Wednesday.

Letlow would have to file to run by Feb. 13.

NBC News previously reported that the White House has assured Letlow that its support would be there if she chooses to jump into the race. But White House officials didn’t want to get involved too early in the primary for fear of alienating Cassidy, who chairs a key committee and has provided some pivotal votes for the GOP last year — including to confirm Health and Human Services Secretary Robert F. Kennedy Jr.

Cassidy voted to impeach Trump for "incitement of insurrection" and has also been critical of Kennedy. However, Cassidy has not brought Kennedy in for an oversight hearing before the Health, Education, Labor, and Pensions Committee since May, despite the secretary's promise to appear before the Committee "on a quarterly basis" if requested.

Cassidy invited Kennedy for a hearing to review changes at the Centers for Disease Control and Prevention in September, but the Senator continues to tell NBC News that there is no date set for that hearing to take place.

This article was originally published on NBCNews.com