Pars is the Iranian sector of the world's largest natural gas deposit, which Iran shares with Qatar across the Gulf. Iran's Fars news agency reported that gas tanks and parts of a refinery had been hit on Wednesday, workers had been evacuated to a safe location and emergency crews were trying to put out a fire.
The attack was widely reported in Israeli media to have been carried out by Israel with the consent of the United States. The Israeli military did not immediately respond to requests for comment.
Qatar, a close US ally which hosts the largest US airbase in the region, called it an Israeli attack without mentioning any US role. The Qatari foreign ministry spokesperson called it a "dangerous and irresponsible" escalation that put global energy security at risk.
Iran's Revolutionary Guards swiftly told Saudi Arabia, the UAE and Qatar to evacuate several energy facilities.
The US and Israel had previously held back from targeting Iran's energy production facilities in the Gulf, a move that could invite retaliation against other producers and make it harder for global markets to recover from what has already been the biggest ever interruption to energy supplies.
But nearly three weeks into the war, there has been no sign of de-escalation.
Israel said on Wednesday it had killed Iran's intelligence minister in the second strike on a top leadership figure in two days, and had authorised the military to target any senior Iranian official it can locate.
Israel also hit central Beirut, destroying apartment buildings in some of the most intense air strikes on the Lebanese capital for decades, on Israel's other front in the war it launched with the US against Iran.
"No one in Iran has immunity and everyone is in the crosshairs," said Defence Minister Israel Katz, who announced that Israel had killed Iran's Intelligence Minister Esmail Khatib a day after killing security chief Ali Larijani.
"The Prime Minister, Benjamin Netanyahu, and I have authorised the Israel Defense Forces to target any senior Iranian official for whom an intelligence and operational opportunity arises, without the need for additional approval."
It appeared to be the first time Israel has publicly stated that it would let the military target enemy officials without seeking special permission from political leaders for missions. Katz did not say when the order had been given.
In Tehran, thousands of people appeared in the streets for a funeral for Larijani and other slain figures. The crowd waved Iranian flags and carried portraits of the dead as a eulogist sang: "Martyrs are leading the way, they've become more alive, burning with love."
Iran retaliated for the killing of Larijani by firing missiles at Israel, which Israeli authorities said killed two people near Tel Aviv. Tehran said it fired overnight on Tel Aviv, Haifa and Beersheba in Israel, and at US bases in Bahrain, Iraq, Jordan, Kuwait, Saudi Arabia and the UAE.
Iranian Foreign Minister Abbas Araqchi said the US and Israel failed to understand that the Islamic Republic was a robust political system that did not depend on any single individual.
The unprecedented disruption to global energy supplies has raised the political stakes for US President Donald Trump. Diesel prices in the United States rose above $US5 ($A7.1) a gallon for the first time since the 2022 inflation surge that eroded support for his predecessor Joe Biden.
Israel has stepped up strikes on Lebanon and a ground assault in the south in pursuit of the Iran-backed Hezbollah group, which has fired across the border in solidarity with Tehran.
Inside Israel, an Iranian missile tore a crater into the pavement and set cars ablaze in a residential area of Holon, just south of Tel Aviv.
