Anti-drone weaponry will be deployed for the first time at tonight's Oscars ceremony amid fears pro-Iranian terrorists may target Hollywood's biggest event.

Snipers and SWAT teams will join more than 1,000 uniformed police officers to form a 'ring of steel' around the Dolby Theatre to protect stars such as Brad Pitt, Leonardo DiCaprio and Jessie Buckley, who is tipped to win Ireland's first best actress Oscar.

Airspace above the venue will be closed throughout the three-hour show amid fears Iranian sleeper cells may launch an attack.

A source close to the production team told The Mail on Sunday: 'Security is always tight but, because of the Iran War, it is unprecedented. There is anti-drone weaponry for the first time as well as radiation monitors and a biological decontamination unit.'

Streets will be sealed off in a one-mile radius around the event with Joint Terrorism Task Force operators and undercover FBI agents supporting the Los Angeles Police Department (LAPD). The source added: 'There are snipers on the rooftops and bomb sniffing dogs.'

LAPD chief Jim McDonnell said his force would be ready for 'any eventuality' including drone attacks or a lone suicide bomber.

FBI agent Akil Davis told the Los Angeles Times: 'Everything's kind of heightened this year, more so than last year.' Of unverified threats that Iran may be preparing to launch a drone attack from vehicles near the venue or even ships sitting off the Californian coast, he said: 'We've got the personnel and the expertise on scene to handle anything should it occur.'

Meanwhile, Ms Buckley is considered 'virtually unbeatable' as best actress for her role as William Shakespeare's wife Agnes in the emotional drama Hamnet.

Michael B Jordan, who plays two roles in vampire movie Sinners, could also scoop the best actor award. The Ryan Cooglar-directed film holds the record for the most Oscar nominations in history with 16 while DiCaprio's One Battle After Another received 13 including best picture and best actor.

It was revealed last night that Barbra Streisand may make a rare live performance to honour her friend Robert Redford in the show's extended In Memoriam segment.

The legendary singer is rumoured to be performing The Way We Were in honour of Redford, her co-star in the 1973 romance, who died in September aged 89.

An academy source said: 'Streisand hasn't performed at the ceremony since [composer] Marvin Hamlisch died. If she does, it will bring the house down. I've been told she will definitely be at the ceremony and will take to the stage for the In Memoriam segment but only a handful of people know whether she will actually perform.'

The 98th Academy Awards will air live on ITV1 and ITVX tonight with red carpet arrivals starting at 10.15pm.