Nebraska Rep. Jeff Fortenberry speaks on Capitol Hill in Washington, DC, on March 27, 2019.
Washington CNN  — 

Republican Rep. Jeff Fortenberry of Nebraska, who was convicted earlier this week in regard to an investigation looking into illegal campaign contributions, will resign from Congress, he announced in a letter to supporters on Saturday.

The resignation will be effective on March 31, per a letter Fortenberry attached to his email to supporters.

Fortenberry’s resignation will create a vacancy in Nebraska’s 1st Congressional District, and Gov. Pete Ricketts, a Republican, will call a special election.

Fortenberry, 61, was found guilty on Thursday of concealing information and making false statements to federal authorities in regard to an investigation looking into illegal campaign contributions for his 2016 reelection campaign.

“Due to the difficulties of my current circumstances, I can no longer effectively serve,” Fortenberry said in the letter to supporters.

Fortenberry was under pressure to resign following the convictions, with both House Speaker Nancy Pelosi and GOP Leader Kevin McCarthy publicly calling on him to step down.

“I think he had his day in court. I think if he wants to appeal, he can go do that as a private citizen,” McCarthy said on Friday. “But I think when someone’s convicted, it’s time to resign.”

Last fall, ahead of the indictment being announced, Fortenberry said in a video uploaded to YouTube that “about five-and-a-half years ago, a person from overseas illegally moved money to my campaign.” But the Nebraska Republican said that he “didn’t know anything about this.”

The indictment stated that an unnamed person, referred to as “Individual H” in the document, acted as a co-host of a 2016 fundraiser for Fortenberry.

According to the indictment, Fortenberry contacted that individual in the spring of 2018 to discuss hosting another event. The court document states that during a June 2018 call, the fundraiser co-host told Fortenberry that the $30,000 in donations “probably did come from” a foreign national.

Campaigns are prohibited from taking contributions from foreign nationals, according to the Federal Election Commission.

But the indictment states that “despite being told by Individual H about the illegal donations, defendant Fortenberry did not file an amended report with the FEC regarding the 2016 fundraiser” and “did not return or otherwise try to disgorge the contributions.” The indictment goes on to say that “it was not until after the FBI and USAO interviewed him in July 2019 that defendant Fortenberry disgorged the contributions.”

Fortenberry is scheduled to be sentenced on June 28. Each charge carries a statutory maximum penalty of five years in federal prison, according to the US Attorney’s office.

Fellow Nebraska Republican Don Bacon, who represents the neighboring 2nd Congressional District, told CNN on Sunday that Fortenberry “did the right thing” by resigning from office.

“It’s always regrettable when someone hurts their life and hurts their family. And so, I wish Jeff well and his family well, and he’s going to do the appeals, but I believe in the justice system, and the justice system spoke,” he told CNN’s Boris Sanchez.

This story has been updated with additional background information.

CNN’s Sarah Fortinsky contributed to this report.