Las Vegas police are ramping up security ahead of the highly anticipated clash after the death cult threatened to bring terror to the city.
Authorities fear ISIS-inspired terrorists may carry out a Barcelona-style van attack on the city’s iconic strip of hotels and casinos.
An ISIS propaganda video featuring images of hotels and casinos in the Sin City has spurred police to increase security for the fight.
The footage was released in May – just days after Manchester bomber Salman Abedi slaughtered 22 outside a pop concert.
Now, three months on, the “credible” threat has sparked police concerns for the big fight between McGregor and Mayweather.
This weekend hundreds of thousands of boxing fans, including many Brits, will descend on the T Mobile Arena to watch the match.
As 20,000 fans flock to the venue, police patrolling the strip will be on standby outside.
Security is expected to be tight, with around 5,000 hotel staff advised to inform police of suspicious activity.
Steel posts are being erect along the strip to thwart a potential vehicle attack.
Officer Jeff Clark, of Las Vegas police, has urged fans to remain vigilant and report any dodgy activity.
Speaking to the Mirror Online, he said: “We are constantly evaluating the ever changing world climate and learning from events, such as Barcelona and London.
“There will be a very visible police presence. We have shifted resources throughout the Las Vegas Valley to focus on the resort corridor.
“We are staffing in excess of 100 special events, most of which are related to the fight, with hundreds of off-duty officers working overtime.”
He urged fans to enjoy the fight, but keep their eyes peeled an report anything they think is suspicious.
Local politician Steve Sisolak added: “There’s always the risk that (an attack) could happen.
“It brings up a sad reminder that every city and town could have things happen whether it’s intentionally or accidentally.”
Fight fans have also raised concerns about a possible terror attack on the Nevada city.
Shaun Marlow, 32, from Leicester, said: “There are a gang of us out here and we can’t wait for the fight.
“But obviously we’re a bit concerned. It’s a high-profile target after all, so we’re trying to keep our wits about ourselves.”