In a post on Truth Social, Trump said the US "knew nothing" of Israel's strike, and threatened an escalation if Iran attacks Qatar again.
If Iran does strike Qatar again, Trump said the US will "will massively blow up the entirety of the South Pars Gas Field at an amount of strength and power that Iran has never seen or witnessed before".
Iran's South Pars is part of the world's largest natural gas field, with both Qatar and Iran operating facilities in the area - Israel is yet to comment.
The price of gas has risen sharply in the UK and Europe following the attack on Qatar's Ras Laffan.