Wednesday's attack on the huge South Pars gas field drove oil prices higher and prompted a threat by Iran to attack oil and gas targets across the Gulf, while it fired missiles at Qatar and Saudi Arabia.
The escalation heightens the unprecedented disruption of global energy supplies that has raised the political stakes for Trump, who joined Israel in attacking Iran nearly four weeks ago.
Qatar's state oil giant QatarEnergy reported "extensive damage" after Iranian missiles hit the Ras Laffan Industrial City that processes about a fifth of global gas supply.
Saudi Arabia said it intercepted and destroyed four ballistic missiles launched toward Riyadh on Wednesday and an attempted drone attack on a gas facility in its east.
On Thursday, Iran again targeted Qatar's gas facilities and its missiles also targeted the Saudi capital.
QatarEnergy "sizeable fires" and extensive damage at several of its liquefied natural gas (LNG) facilities targeted in missile attacks early on Thursday.
Trump said the United States did not have advance knowledge of Israel's attack, adding that Qatar had not been involved.
"Israel, out of anger for what has taken place in the Middle East, has violently lashed out at a major facility known as South Pars Gas Field in Iran," Trump posted on X.
"Unfortunately, Iran did not know this, or any of the pertinent facts pertaining to the South Pars attack, and unjustifiably and unfairly attacked a portion of Qatar's LNG Gas facility.
"NO MORE ATTACKS WILL BE MADE BY ISRAEL pertaining to this extremely important and valuable South Pars Field unless Iran unwisely decides to attack a very innocent, in this case, Qatar.
"In which instance the United States of America, with or without the help or consent of Israel, 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."
Earlier, the Wall Street Journal said Trump had approved of Israel's plan to attack Iran's natural gas field.
South Pars is the Iranian sector of the world's largest natural gas deposit, which Iran shares with Qatar, a close US ally and host of the United States' biggest military base in the Gulf.
Since the start of the conflict, Tehran has targeted not just Israel, but US diplomatic and military facilities across the Gulf and warned its neighbours not to host attacks on Iran.
With de-escalation nowhere in sight, Trump is considering sending thousands more US troops to the Middle East, according to a US official and three people familiar with the planning.
Those troops could be used restore the safe passage of oil tankers through the Strait of Hormuz, a chokepoint for a fifth of the world's oil trade.
The foreign ministers of 12 Muslim-majority countries meeting in Riyadh denounced Iran's strikes on Gulf neighbours and called for an immediate halt.
Iran's targeting of residential areas and civilian infrastructure, such as oil facilities, airports and desalination plants, could not be justified under any circumstances, the ministers said in a statement.
"This pressure from Iran will backfire politically and morally and certainly we reserve the right to take military actions, if deemed necessary," Saudi Foreign Minister Prince Faisal bin Farhan told a press conference after the diplomats met in Riyadh.
The UAE shut down its Habshan gas facility after it intercepted missiles fired in what its foreign ministry called a "terrorist attack" by Iran.
Israel killed Iran's intelligence minister Esmail Khatib on Wednesday, a day after killing powerful security chief Ali Larijani, and Israeli Defence Minister Israel Katz said "no one in Iran has immunity and everyone is in the crosshairs".
He and Prime Minister Benjamin Netanyahu had authorised the Israeli military "to target any senior Iranian official for whom an intelligence and operational opportunity arises, without the need for additional approval."
More than 3000 people have been killed in Iran since the US-Israeli attacks began on February 28, the US-based Iran human rights group HRANA estimates.
Authorities in Lebanon say 900 have been killed there and 800,000 forced to flee their homes.
Iranian attacks have killed people in Iraq and across the Gulf states, and at least 13 US military service members have been killed in the war.
