Roll Call newspaper reported Monday that Sen. Larry Craig of Idaho was apprehended June 11 by a plainclothes police officer investigating complaints of lewd behavior in an airport men's room.
Roll Call reports on the U.S. legislature.
Craig denied any inappropriate conduct in a prepared statement, and said he now regrets his guilty plea.
"At the time of this incident, I complained to the police that they were misconstruing my actions. I was not involved in any inappropriate conduct," he said. "I should have had the advice of counsel in resolving this matter. In hindsight, I should not have pled guilty. I was trying to handle this matter myself quickly and expeditiously."
Congress is currently in recess, and Craig's office said he was on vacation in Idaho with his family, with no public appearances scheduled.
Craig, 62, paid a $500 fine when he entered his guilty plea on August 8 in Hennepin County Municipal Court in Bloomington, Minnesota, according to state criminal records.
CNN confirmed that Craig was sentenced to 10 days in jail but that sentence was stayed.
Minnesota law defines disorderly conduct as brawling, disturbing a meeting or engaging in "offensive, obscene, abusive, boisterous or noisy conduct."
According to Roll Call, the arresting officer alleged that Craig lingered outside a rest room stall where the officer was sitting, then entered the stall next door and blocked the door with his luggage.
According to the arrest report cited by Roll Call, Craig tapped his right foot, which the officer said he recognized "as a signal used by persons wishing to engage in lewd conduct."
The report alleges Craig then touched the officer's foot with his foot and the senator "proceeded to swipe his hand under the stall divider several times," according to Roll Call.
At that point, the officer said he put his police identification down by the floor so Craig could see it and informed the senator that he was under arrest, before any sexual contact took place.
Idaho's senior senator is married with three grown children and nine grandchildren. A former rancher, Craig was first elected to the Senate in 1990, after serving a decade in the House. His seat is up for re-election in 2008.
Last fall, Craig's office publicly denied assertions by Internet blogger Mike Rogers that the senator is gay. Craig's office dismissed speculation about the senator's sexuality as "completely ridiculous."
In 1982, Craig denied rumors that he was under investigation as part of a federal probe into allegations that lawmakers on Capitol Hill had sexual relationships with congressional pages, saying the "false allegations" made him "mad as hell."
He was never implicated in that investigation, which eventually led to ethics charges against two other congressmen.
In recent years, Craig's voting record has earned him top ratings from social conservative groups such as the American Family Association, Concerned Women for America and the Family Research Council.
He has supported a federal constitutional amendment banning same-sex marriage, telling his colleagues that it was "important for us to stand up now and protect traditional marriage, which is under attack by a few unelected judges and litigious activists."
In 1996, Craig also voted in favor of the Defense of Marriage Act, which denies federal recognition to same-sex marriages and prevents states from being forced to recognize the marriages of gay and lesbian couples legally performed in other states.
Craig has also opposed expanding the federal hate crimes law to cover offenses motivated by anti-gay bias and, in 1996, voted against a bill that would have outlawed employment discrimination based on sexual orientation, which failed by a single vote in the Senate.
Craig has endorsed former Massachusetts Gov. Mitt Romney in the 2008 presidential race. The senator was named in February, along with Sen. Robert Bennett of Utah, as Romney's liaison to build support among GOP senators.
Monday night, Romney's presidential campaign announced Craig was stepping down."He didn't want to be a distraction, and we accept his decision," the Romney campaign said in a statement. Access to a YouTube video in which Craig praised Romney was also blocked.