Lawyers for the illusionist say the allegations are "false and scurrilous".
There will be no live audience at June's Atlanta event, which will mark the pair's first on-stage clash in four years.
Slovakia's outgoing president expressed shock after the shooting of PM Robert Fico.
The weapons transfer comes as Israeli tanks were spotted advancing deeper into residential areas of Rafah.
Slovak PM Robert Fico is was shot a number of times in what officials call an assassination attempt.
Ukraine says it has moved troops to "advantageous positions" as Russia intensifies its attacks on the region.
PM Robert Fico was shot in what the Slovak Interior Ministry said was an assassination attempt.
Israeli forces and Hamas fighters say they are engaged in fierce clashes in north and south Gaza.
The riots come in response to the French parliament giving French residents there more voting rights.
Robert Fico was shot as he left a meeting in Handlova, central Slovakia - a suspect has been arrested.
Staff scaled a ladder to discover graffiti thought to date back to the 1789 French Revolution.