Rep. Jeff Fortenberry, R-Neb., announced Saturday that he will resign from Congress after he was convicted by a California jury for lying to authorities about an illegal campaign donation from a foreign national.

In a letter to his colleagues in the House, Fortenberry, who has served as Congressman for Nebraska's 1st congressional district since 2005, said he was resigning from Congress, effective March 31.

NEBRASKA CONGRESSMAN FOUND GUILTY OF LYING TO FBI ABOUT FOREIGN CAMPAIGN CONTRIBUTION

"It has been my honor to serve with you in the United States House of Representatives," Fortenberry wrote in the letter. "Due to the difficulties of my current circumstances, I can no longer effectively serve."

U.S. Rep. Jeff Fortenberry, R-Neb., speaks on Capitol Hill, Wednesday, March 27, 2019, in Washington.

U.S. Rep. Jeff Fortenberry, R-Neb., speaks on Capitol Hill, Wednesday, March 27, 2019, in Washington. (AP Photo/Andrew Harnik File)

"It has been my pleasure to call many of you friends," he added. "May God bless you as you labor for the good of our country, help those in need, and strive for what is right and just."

Fortenberry’s resignation letter opened with a poem, "Do It Anyway," that’s associated with Mother Teresa. One line from the poem says: "What you spend years building, someone could destroy overnight. Build anyway."

In an email, Fortenberry thanked his constituents for "entrusting me with the great responsibility of governing our nation."

"When I first ran for Congress, I said that I would focus on our national security, economic security, and family security," he wrote. "It is my sincerest hope that I have made a contribution to the betterment of America, and the wellbeing of our great state of Nebraska. Due to the difficulties of my current circumstances, I can no longer serve you effectively."

Fortenberry’s announcement followed concerted pressure from political leaders in Nebraska and Washington for him to step down. House Speaker Nancy Pelosi and House Minority Leader Kevin McCarthy on Friday urged Fortenberry to resign.

House Speaker Nancy Pelosi, D-Calif., and House Minority Leader Kevin McCarthy, R-Calif.

House Speaker Nancy Pelosi, D-Calif., and House Minority Leader Kevin McCarthy, R-Calif. (Anna Moneymaker/Getty Images)

Nebraska Republican Gov. Pete Ricketts also pushed for Fortenberry to resign, calling it the "right thing for his constituents"

The Nebraska congressman was charged last year after being interviewed by two FBI agents who were investigating Nigerian billionaire Gilbert Chagoury who gave Fortenberry a $30,000 campaign contribution at a Los Angeles fundraiser before the 2016 election and has donated to other campaigns.

The nine-term Republican congressman’s defense has maintained his innocence, arguing that the investigators knew he was unaware of the donation at the time but directed an informant to feed him the information in a 10-minute recorded call with the intention of trying to prosecute him. They claimed the FBI used false pretenses a year later to interview him and charge him after he couldn’t remember the recorded conversation.

U.S. Rep. Jeff Fortenberry, R-Neb., center, and wife, Celeste, left, arrive at the federal courthouse for his trial in Los Angeles, Wednesday, March 16, 2022.

U.S. Rep. Jeff Fortenberry, R-Neb., center, and wife, Celeste, left, arrive at the federal courthouse for his trial in Los Angeles, Wednesday, March 16, 2022. (AP Photo/Jae C. Hong, File)

Dr. Elias Ayoub, who hosted Fortenberry in Los Angeles in 2016, confessed in a recorded 2018 call with the congressman that he distributed $30,000 to friends and relatives who attended the fundraiser so they could write checks to Fortenberry's campaign. During the call in 2018, Ayoub had been cooperating with the FBI. Ayoub said the money probably came from Chagoury, who admitted in 2019 to funneling $180,000 in illegal campaign contributions to four campaigns and agreed to pay a $1.8 million fine.

In 2019, Fortenberry, unaware that the call was being recorded, told the FBI that he didn’t receive any foreign donations or so-called conduit contributions, where the money was distributed to straw donors.

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Fortenberry "chose to conceal the truth, he chose to lie to federal investigators when they came to ask question [sic]… believing his status and privilege as a congressman would shield him from his choices," prosecutor Susan Har said during closing arguments, according to KETV in Omaha. 

Each count carries a maximum sentence of five years in prison.

Fox News' Brie Stimson and the Associated Press contributed to this article.