Rep. Trey Radel (R-Fla.), who was arrested and charged with cocaine possession last October, is resigning, according to Politico.

Radel pleaded guilty to cocaine possession in November and was sentenced to one-year probation.

A Radel spokesman confirmed his resignation to The Huffington Post on Monday.

Radel apologized to his GOP colleagues, his constituents and his family after the incident, saying he was "profoundly sorry."

In early January, Radel's spokesman said he would return to Congress six weeks after pleading guilty and checking into a rehab program. Many Republicans -- including the Republican Party of Florida and the state's governor, Rick Scott -- called on the congressman to step down after his arrest.

UPDATE -- 10:45 a.m. ET: In a letter, Radel wrote that his resignation is effective Monday at 6:30 pm.

"Regardless of some personal struggles in 2013, this year has already been tremendously positive as I focus on my health, family and faith," he said in a letter to House Speaker John Boehner. "Unfortunately, some of my struggles had serious consequences. While I have dealt with those issues on a personal level, it is my belief that professionally I cannot fully and effectively serve as a United States Representative to the place I love and call home, Southwest Florida."

Read Radel's letter below:

This story has been updated with more information on Radel and confirmation of his resignation.