Military strikes between Iran and Israel have prompted concern about potential damage and disruption to the region's important oil and gas fields and infrastructure.
Below are details about these sites and about how they have been affected so far:
SOUTH PARS GAS FIELD
Israel struck an installation at the South Pars offshore gas field on June 14 where Iran has partially suspended production. South Pars is part the world's largest natural gas reserve which Iran shares with Qatar.
The attack struck four units of Phase 14 of South Pars, around 200 kilometres from Qatar's installations, many of which are joint ventures with international firms, including U.S. giants ExxonMobil and ConocoPhilips.
TEHRAN FUEL DEPOT AND REFINERY
Israel struck a Tehran fuel depot and an oil refinery near the capital on June 14, Iran said, but authorities said the situation was under control.
HAIFA OIL REFINERY
Israel's Bazan Group shut down its Haifa oil refinery, the country's largest, on June 16 after its power station was damaged in an Iranian attack. The refinery has a crude processing capacity of 197,000 barrels per day (bpd).
WHY SOUTH PARS MATTERS
South Pars makes up around a third of the world's largest reservoir of natural gas. Iran shares the reservoir with major gas exporter Qatar, which calls its field the North Dome.
Sanctions and technical constraints have meant most gas Tehran produces there is used domestically but it also exports some.
Iran exported about 15.8 billion cubic metres of gas in 2023, according to data by the Gas Exporting Countries Forum, a grouping of gas exporter nations.
The entire reservoir contains an estimated 1,800 trillion cubic feet of usable gas - enough to supply the world's needs for 13 years, or to generate enough electricity to supply the U.S. for more than 35 years.
IRAN'S OIL Iran is OPEC's third largest oil producer and extracts about 3.3 million bpd of crude oil, and another 1.3 million bpd of condensate and other liquids, totalling about 4.5% of global supplies.
Its exports in recent months have reached 1.8 million bpd, their highest level since 2018, data from Kpler showed, driven by strong Chinese demand.
It exports 90% of its crude via Kharg Island. The U.S. tightened sanctions on Tehran in 2018 after U.S. President Donald Trump exited a nuclear accord.
Iran's oil exports fell to nearly zero but rebounded under U.S. President Joe Biden, with analysts saying sanctions were less rigorously enforced and Iran succeeded in evading them.
Iran is exempt from OPEC+ output restrictions and China does not recognise the sanctions imposed on Tehran, meaning some Chinese private refiners have been placed on the U.S. Treasury's sanctions list.
Analysts say Saudi Arabia and other OPEC members could compensate for any drop of Iranian supply by using their spare capacity to pump more.
