AC/DC guitarist Angus Young says he doesn't yet know if the band will continue on after completing their current world tour this fall.

The band has weathered the departures of three longtime members (guitarist Malcolm Young, drummer Phil Rudd and singer Brian Johnson) in recent years, and bassist Cliff Williams announced he will also retire at the end of this tour.

"At this point, I don't know," he tells Rolling Stone when asked what the group's future holds. "We were committed to finishing the tour. Who knows what I'll feel after? When you sign on and say, 'I'm gonna do this and that,' it's always good to say at the end of it, 'I've done all I said I would do.'"

Young explains that Williams told him the Rock or Bust tour would be his last "before we'd even started touring," and that the group was also aware of the hearing problems that would eventually force Johnson off the road right from the start of the trek: "Each show he did, he had to get monitored and treated. But it was becoming too hard for him."

He also revealed that "it's hard to communicate" with his brother Malcolm, who was forced to retire from the group due to a battle with dementia. "I do pass on messages. I can't be 100 percent sure it goes in there. But I let him know there are a lot of people missing him."

When asked if he now thinks the group should have called it quits once they learned Malcolm couldn't continue, Young says, "That might be the case. But Malcolm was always one to battle through. He would look at me in times of crisis and go, 'We'll just go in and do some work. We'll sit and write some songs.' He had that drive, and I feel obligated to keep it going, maybe because I was there in the beginning with him."

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