Las Vegas Casino billionaire Sheldon Adelson has threatened to sue the Democratic Congressional Campaign Committee (DCCC) if it does not immediately retract and apologize for what Adelson's lawyers call defamatory statements, "falsely accusing Mr. Adelson of encouraging and profiting from prostitution."

ABC News obtained a copy of the letter sent to the DCCC, which claimed articles posted on the DCCC's website are "outrageous and completely untrue."

While Adelson's lawyer would not comment on the threatened lawsuit, first reported by the Las Vegas Sun, a spokesman for Adelson told ABC News that he believes the letter and a related legal document "very clearly" speak for themselves.

The DCCC picked up an Associated Press article from June that reported an estranged former executive of the Las Vegas Sands Corp. in China alleged in court documents related to a lawsuit that Adelson approved and knew of prostitution at the casino's Macau location.

Adelson's spokesman denied the claim after the AP report surfaced, and his spokesman repeated today the assertion that the prostitution claims are false.

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DCCC spokesman Jesse Ferguson told ABC News that the DCCC just received the letter from Adelson's legal team, will be internally reviewing it and did not immediately have a response.

Because Adelson is one of the most influential donors in the Republican Party, the DCCC asked on its website in regard to the prostitution claim, "What will Speaker Boehner, Leader Cantor and House Republicans do with their Chinese prostitution money?"

In a separate post, Ferguson is quoted saying, "It's past time for House Republicans to reject the support of these groups funded by foreign money from a Chinese prostitution strategy."

Adelson's lawyers claim the DCCC's statements were "widely repeated" online and caused "serious and irreparable injury to Mr. Adelson and his family."