The sabotage, which analysts said marked an escalation in the shadow war between Israel and Iran, caused sweeping disruption in several provinces.
Israel carried out covert attacks on two major natural gas pipelines inside Iran this week, disrupting the flow of heat and cooking gas to provinces with millions of people, according to two Western officials and a military strategist affiliated with Iran’s Revolutionary Guards Corps.
The strikes represent a notable shift in the shadow war that Israel and Iran have been waging by air, land, sea and cyberattack for years.
Israel has long targeted military and nuclear sites inside Iran — and assassinated Iranian nuclear scientists and commanders, both inside and outside of the country. Israel has also waged cyberattacks to disable servers belonging to the oil ministry, causing turmoil at gas stations nationwide.
But blowing up part of the country’s energy infrastructure, relied on by industries, factories and millions of civilians, marked an escalation in the covert war and appeared to open a new frontier, officials and analysts said.
“The enemy’s plan was to completely disrupt the flow of gas in winter to several main cities and provinces in our country,” Iran’s oil minister, Javad Owji, told Iranian media on Friday.
Mr. Owji, who had previously referred to the blasts as “sabotage and terrorist attacks,” stopped short of publicly blaming Israel or any other culprit. But he said that the goal of the attack was to damage Iran’s energy infrastructure and stir domestic discontent.
The office of Israel’s Prime Minister Benjamin Netanyahu declined to comment.
The Western officials and the Iranian military strategist said the gas pipeline attacks by Israel required deep knowledge of Iran’s infrastructure and careful coordination, especially since two pipelines were hit in multiple locations at the same time.
One Western official called it a major symbolic strike that was fairly easy for Iran to repair and caused relatively little harm to civilians. But, the official said, it sent a stark warning of the damage that Israel could inflict, as conflict spreads across the Middle East and tensions rise between Iran and its adversaries, notably Israel and the United States.
The Western officials said Israel also caused a separate blast on Thursday inside a chemical factory on the outskirts of Tehran that rattled a neighborhood and sent plumes of smoke and fire into the air. But local officials said the factory explosion, which took place on Thursday, stemmed from an accident in the factory’s fuel tank.
Iran has said that it does not want a direct war with the United States, and it has denied being involved in either the Oct. 7 terrorist attacks against Israel or the various attacks against American and Israeli targets in the region since then.
But Iran supports and arms a network of proxy militia that have been actively fighting with Israel and United States, including the Houthis in Yemen, Hezbollah in Lebanon and militants in Iraq and Syria. Iran has also armed and trained Hamas and other Palestinian fighters.
The strikes and counter-strikes across the region have escalated in recent months. Israel has killed two senior Iranian commanders in Syria, while the United States has struck military bases connected to the Revolutionary Guards and its proxies in Iraq and Syria after three American soldiers were killed in a drone attack.
Iran also suffered one of the largest terrorist attacks in its history in January, when suicide bombers killed about 100 people in Kerman during a ceremony for a top general, Qassim Suleimani, killed by the United States four years ago. ISIS claimed responsibility for the suicide attack.
Now, the Western officials say, Israel has attacked inside Iran’s borders with back-to-back explosions that have unnerved Iranians.
“This shows that the covert networks operating in Iran have expanded their target list and advanced beyond just military and nuclear sites,” said Shahin Modarres, a Rome-based security analyst focused on the Middle East. “It’s a major challenge and reputation blow for Iran’s intelligence and security agencies.”
The sabotage targeted several points along two main gas pipelines in the provinces of Fars and Chahar Mahal Bakhtiari on Wednesday. But the disruption in service stretched to residential homes, government buildings and major factories in at least five provinces across Iran, according to Iranian officials and local media reports.
The pipelines carry gas from the south to major cities like Tehran and Isfahan. One of the pipelines runs all the way to Astara, a city near Iran’s northern border with Azerbaijan.
Energy experts estimated that the attacks on the pipelines, which each run for about 1,200 kilometers or 800 miles and carry 2 billion cubic feet of natural gas per day, knocked out about 15 percent of Iran’s daily natural gas production, making them particularly sweeping assaults on the country’s critical infrastructure.
“The level of impact was very high because these are two significant pipelines going south to north,” said Homayoun Falakshahi, a senior energy analyst at Kpler. “We have never seen anything like this in scale and scope.”
On Friday, Mr. Owji, the oil minister, said that technical teams from the ministry had worked around the clock to repair the damage, and that the disruption had been minimal and service restored.
But his assessment was at odds with the comments of local governors and officials from Iran’s national gas company, who had described widespread outages of service in five provinces, forcing the closure of government buildings. On social media, Iranian energy experts advised people in the affected areas, where in some places temperatures dropped below freezing, to dress warmly.
The blasts happened at around 1 a.m. local time, terrifying residents, who fled their homes and poured into the streets, according to Iranian media reports. On social media, people described blasts so loud that they woke up thinking a bomb had been dropped. No casualties were reported.
Saeid Aghli, an official with the national gas company, told Iranian media that officials immediately called an emergency meeting attended by the oil minister, officials from the foreign ministry and representatives from all of Iran’s intelligence and security services. Mr. Aghli said the sabotage was intended to take out about 40 percent of the country’s gas transmission capacity.
How the pipelines were struck — with drones, explosives attached to pipes or some other means — remains unclear. Iran’s energy infrastructure has been targeted in the past, but those incidents were much smaller in scope and scale, analysts said.
The military strategist affiliated with the Revolutionary Guards Corps — who, like the other officials, was not authorized to speak publicly — said the Iranian government believed Israel was behind the attack because of the complexity and scope of the operation. The attack, he said, almost certainly required the help of collaborators inside Iran to figure out where and how to strike.
He noted that major pipelines in Iran, which carry gas across vast distances that include mountains, deserts and rural fields, are patrolled by guards in outposts along the length of the pipes. The guards check their areas every few hours, he said, so the attackers may have had knowledge of their breaks, when the area would remain unmanned.
Mr. Falakshahi, the energy analyst, said the blasts exposed the vulnerability of the country’s critical infrastructure to attacks and sabotage. He said that Iran, the third largest producer of natural gas in the world, has about 40,000 kilometers of natural gas pipelines, mostly underground. He added that the pipelines are primarily for domestic consumption and that, because of sanctions, Iran’s export of gas was minimal and limited to Turkey and Iraq.
“It’s very difficult to protect this very extensive network of pipelines unless you invest billions in new technology,” Mr. Falakshahi said. He added that repairing the damaged pipelines would require shutting off the gas and then replacing the pipes, which could take days.
