An Iranian missile strike caused extensive damage to Qatar's largest gas plant on Wednesday evening, escalating the destructive war on both sides of the Gulf and triggering a diplomatic crisis between the previously friendly nations.
Qatar expelled two Iranian diplomats from the country after missiles struck the Ras Laffan plant, the largest liquefied natural gas plant in the world.
Iran claimed the strike was a retaliation to Israel's bombing of the South Pars gas field earlier on Wednesday.
QatarEnergy said emergency workers were "deployed immediately to contain the resulting fires," at the facility after it was "the subject of missile attacks".
Footage shared online showed huge fires at a section of the facility.
Qatar's foreign ministry condemned what called a "brutal Iranian attack targeting Ras Laffan" saying the targeting represented a "direct threat to its national security".
In response, the country declared the security and military attache in Iran's embassy as "persona non grata" and ordered them to leave the country within 24 hours.
European gas prices soared by as much as 35 percent following the attacks on Thursday amid fresh concerns about the continent's energy supplies. Qatar is a major supplier of natural gas to Europe.
The attack came a few hours after Israeli warplanes struck Iranian facilities in the massive South Pars reservoir, the world's largest gas field shared by Iran and Qatar.
Iran then warned of "uncontrollable consequences" of attacks on energy infrastructure and threatened to destroy energy infrastructure in the Gulf if Israel or the US continued strikes. Iran's Revolutionary Guards vowed further attacks "until it is completely destroyed", and a "much more severe" response.
Iran also launched ballistic missiles at Saudi Arabia on Wednesday evening, coinciding with a meeting of Arab and Islamic diplomats meeting to discuss ending the regional war.
Four people were injured when missile shrapnel fell on a residential area in Riyadh, the civil defence said.