A top Republican Party official and casino mogul is denying a report that he assaulted female employees in a decades-long pattern of abuse.

Steve Wynn is accused of harassing massage therapists and forcing one staff member to have sex with him, reports the Wall Street Journal.

“The idea that I ever assaulted any woman is preposterous,” Mr Wynn said in a statement on Friday afternoon.

He blamed his ex-wife, who he is fighting in court, for the “slander”.

“The instigation of these accusations is the continued work of my ex-wife Elaine Wynn, with whom I am involved in a terrible and nasty lawsuit,” the 75-year-old billionaire said in a statement that his public relations team sent to the BBC.

Following the report, Wynn Resorts stocks dropped by more than 10%.

Regulators in Massachusetts, where Mr Wynn is building a casino outside Boston, say they are “taking very seriously the troubling allegations”, and have launched a review of his actions.

“The suitability and integrity of our gaming licensees is of the utmost importance, and ensuring that suitability is an active and ongoing process,” a spokeswoman said in a statement.

A spokesman for Wynn Resorts would not comment on whether Mr Wynn, who has donated millions to political campaigns, planned to continue in his role as finance chairman of the Republican National Committee (RNC).

The RNC did not immediately respond to a BBC request for comment.

During his campaign for president, Donald Trump described his fellow businessman as “a great friend”.

According to the Wall Street Journal, which said it had interviewed dozens of people who had worked with Mr Wynn, he is accused of engaging in a pattern of abuse in which he often harassed massage therapists while alone in his private office.

The gambling industry giant paid $7.5m (£5.2m) to one manicurist who alleged she had been forced into sex by Mr Wynn, the paper claims citing court documents.

Female employees would fake appointments in order to avoid seeing him, or enlist others to pretend to be their assistants in order to avoid being alone with him.

Some would even hide in bathrooms or closets if they heard he was coming to their salon, the paper claimed.

Some of the women told the paper that they felt intimidated by the presence of one or more German Sheppard dogs in his office, which they said were taught to respond to commands in German.