Rory McIlroy says it is “sad” that this week’s US Open is being overshadowed by discussions about the LIV Golf tour.

The PGA Tour suspended 17 members who chose to play in the LIV Golf opener, but the USGA – which runs the US Open – has allowed them to compete this week.

“This is one of the biggest tournaments and the conversation is filled with something out of leftfield,” he said.

“These [majors] will always be the biggest tournaments in the world and no amount of money will change that and that’s a great thing.”

McIlroy, 33, warmed up for this week’s US Open at Brookline Country Club in Boston by successfully defending his Canadian Open title on Sunday, holding off Tony Finau and US PGA Championship winner Justin Thomas in a thrilling final-round in front of an energetic Ontario crowd.

And four-time major winner McIlroy believes LIV Golf events will never boast crowds to rival the PGA Tour.

“It’s the cloud that’s hanging over golf at the minute. We’re at a major and it’s what everyone wants to talk about. It’s on everyone’s mind,” said the Northern Irishman, who starts this week as world number three.

“Those crowds on Sunday in Canada, LIV’s never going to have that. Last week meant something. What they’re doing over there doesn’t mean anything apart from collecting a ton of money so I’m proud of the show we put on.

“It’s the competitive integrity – you’re up against the best.”

The LIV Golf tour, headed by former world number one Greg Norman and backed by Saudi Arabia’s Public Investment Fund (PIF), boasts a prize fund of $250m (£200m) for 2022, while an extra £1.6bn has been secured to expand it to a 14-event league by 2024.

Having already recruited six-time major winner Phil Mickelson and former world number one Dustin Johnson, LIV Golf bolstered its roster considerably with the addition of 2020 US Open champion Bryson DeChambeau.

In February, McIlroy said the breakaway tour was “dead in the water” but he admitted on Tuesday that he was “wrong” to have taken players’ statements outlining their loyalty to the PGA Tour – like Johnson – “at face value”.

“You had people committed to the PGA Tour, that’s the statements that were put out,” he said. “People went back on that, so I guess I took them at their word, and I was wrong.”

Defending PGA Tour the ‘right thing to do’

Along with world number five Thomas, McIlroy has become one of the PGA Tour’s staunchest defenders and said that assuming such a leadership role was the “right thing to do”.

“The PGA Tour was created by people and tour players that came before us, the likes of Jack Nicklaus and Arnold Palmer,” said McIlroy, who won the 2011 US Open for the first of his four majors and is this week aiming to end an eight-year winless streak in golf’s biggest events.

“They created something and worked hard for something, and I hate to see all the players that came before us and all the hard work that they’ve put in just come out to be nothing.”

On Monday, Mickelson held another uncomfortable news conference in which he expressed “the deepest sympathy and empathy” for the families who lost loved ones in the 9/11 terror attacks after a letter written by Terry Strada, the national chair of 911familiesunited.org, criticised the US players for joining the LIV Golf tour.

The 9/11 terror attacks on the United States in 2001 killed almost 3,000 people and according to an FBI declassified document, 15 of the 19 plane hijackers in the attack were Saudi nationals.

Asked if he understood the 9/11 families’ point of view given the Saudi influence in the fledgling golf tour, McIlroy said: “Yeah, of course I do.

“I’m sure not every Saudi Arabian is a bad person. We’re talking about this in such a generalised way.

“I’ve spent a lot of time in the Middle East, and the vast majority of people that I’ve met there are very, very nice people, but there are bad people everywhere.

“The bad people that came from that part of the world did some absolutely horrendous things.

“Of course, I understand where these families are coming from.

“Everything is just so intertwined, and it’s hard to separate sport from politics, dirty money from clean money. It’s a very convoluted world right now.

“I certainly empathise with those families, I have friends that lost people in 9/11, and it’s a really tragic thing.

“I certainly understand their concerns and frustrations with it all.”