The chairman of the US Joint Chiefs of Staff has said an assessment of the destruction sustained at Iran’s nuclear facilities will take time to confirm, but said initial reports indicated heavy damage, Al Jazeera reports.

“I think PDA [preliminary damage assessment] is still pending and it would be way too early for me to comment on what or what may not still be there,” General Dan Caine told reporters at the Pentagon.

However, he added, initial assessment indicated that “all three sites sustained extremely severe damage and destruction”.

He declined to comment on specific moves taken to protect US troops based in the Middle East from potential Iranian retaliation. “Our joint force remains ready to defend the United States — our troops and our interests in the region,” said Caine.