Roy Moore explained in a statement late Tuesday afternoon why he withdrew from a long-scheduled forum with U.S. Sen. Luther Strange at Samford University.

The forum's sponsor, Alabama Policy Institute, has ties to the Senate Leadership Fund that has spent millions in attack ads against Moore and, previously, U.S. Rep. Mo Brooks during the Republican primary.

The runoff between Moore and Strange is Sept. 26.

Moore also called for a debate with Strange "mano a mano" without the constraints of a moderator. A definition of the Spanish phrase: "An intense fight or contest between two adversaries."

Caleb Crosby, the president and CEO of API, is also listed as the treasurer for the Senate Leadership Fund, according to information provided to the Federal Election Commission.

The SLF has aired waves of radio, TV and digital attack ads against Brooks and Moore to boost the candidacy of Strange. The SLF is influenced by Senate Majority Leader Mitch McConnell.

The Samford forum was scheduled for Sept. 21 and its cancellation was reported earlier Tuesday by AL.com. Cameron Smith, an AL.com columnist, was scheduled to be the forum's moderator.

In the statement, Moore said "it was not disclosed to me or my campaign" about Crosby's ties to the SLF.

"The Senate Leadership Fund is responsible for millions of dollars' worth of malicious and false ads designed to stain my character and reputation," Moore's statement said. "I have asked my opponent repeatedly to denounce these ads against me, my wife and my family as he knows that the content contained therein is completely false.

"However, Luther Strange has not done so. In fact, he has warmly embraced McConnell's Senate Leadership Fund and Caleb Crosby as his key allies. The fact that this debate was being hosted by the treasurer of a group so partial to my opponent's personal interests is yet another Washington trick - the same kind of tricks despised by the people of Alabama."

The Strange campaign issued a statement earlier Tuesday criticizing Moore for withdrawing from the forum.

"What is Roy Moore afraid of? What is Roy Moore hiding?" Strange spokesman Cameron Foster said in the statement. "Voters should ask themselves, if Roy Moore refuses to answer questions from voters, will he listen to their concerns in elected office?"

In his statement, Moore said that he has attended eight Republican forums during the primary at which Strange did not attend.

"I find it hypocritical that Luther Strange is now suggesting that I am the one who is ducking debates," Moore said. "We shall see who is ducking debates."

He then spelled out terms for a debate he wants with Strange.

"I propose a public debate, mano a mano, no tricks, no moderators, no questions from the press," Moore said in the statement. "Just Luther Strange and me on the stage presenting our issues and the opponents' responses thereto. All statewide press and TV present. A timekeeper will be selected by mutual agreement.

"We will get to the truth about Luther Strange's appointment deal with Gov. Bentley while he was under investigation by the Attorney General's office, why Luther Strange sided with Mitch McConnell to support the very Senate gamesmanship that has sunk President Trump's agenda, the basis for the false accusations against me, and why Luther Strange has taken millions in Washington special interest money for his campaign. We will do this Lincoln-Douglas style and have a real debate."