Israeli strikes targeting Iranian energy production facilities, manufacturing plants and aviation signaled the start of a wider and more intense phase of the conflict Sunday, as Israeli war planes pursued new targets deeper in Iran’s cities and towns.

Tehran residents reported the heaviest wave of attacks yet on Sunday afternoon, with explosions ringing out every half hour. The Israeli military reported striking “more than 80 targets” in Tehran alone overnight Saturday and by Sunday afternoon it said over 250 targets and more than 720 components had been struck.

The targets appear to indicate an expansion of Israel’s war aims beyond the Iranian nuclear facilities that consumed the first days of the conflict. By striking Iranian industry, local security forces and infrastructure, Israel is aiming to degrade the Iranian state, further damage the country’s already-reeling economy and possibly trigger regime change, according to analysts and former officials.

The shift appeared to begin Saturday night with strikes on energy infrastructure. Israel attacked Iran’s South Pars, the world’s largest natural gas field, partially suspending production and igniting a fire. Another attack on a fuel depot outside Tehran ignited a massive blaze that drew a crowd snapping mobile video and photos.

Elsewhere Sunday, strikes hit airports, electronics manufacturing plants, police stations, an airplane maintenance site and an office that coordinated Tehran’s mosques, according to social media video and state media reports. Many of the aftermath videos from urban areas showed strike locations just yards away from traffic and pedestrians. There was no immediate information on casualties from Iranian authorities.

In Mashhad, a city on Iran’s eastern edge near the border with Turkmenistan, a strike hit a small regional airport. Ali, a 45-year old computer engineer and local resident, said he could see plumes of smoke from the roof of his building.

“I wouldn’t think that they strike as far as Mashhad. I am in so much shock. I am trying to understand what they are pursuing with these kinds of attacks,” he told The Washington Post in a phone interview. He, like others, spoke on the condition that he only be identified by his first name for fear of retribution.

He said many of his friends and family were happy when the first Israeli strikes took out senior Iranian military leaders. “But now things are moving toward much higher destruction,” he said, wondering what Israel was targeting with the dozens of attacks across the country. “Are they trying to increase rage to provoke the Islamic Republic to accept any kind of deal? I can’t really understand.”

Tehran residents also reported a number of explosions that appeared to target single vehicles in the city, stoking suspicion that targeted killings were being carried out with car bombs or small drone attacks.

“It sure does feel like this is a regime change ending, rather than taking out the nuclear program,” said Richard Nephew, a former State Department and White House official in the Obama administration specializing in Iran. Israel may have decided that the best way to prevent Iran from obtaining a nuclear weapon was to topple the Iranian regime, he said, but cautioned such a strategy was “a high-risk maneuver.”

“A lot of things have to go right to make that work. A lot of assumptions about Iranian power structures have to play out,” he said. Israeli Prime Minister Benjamin Netanyahu and his allies have framed the conflict as an opportunity to remove the Islamic regime and have cited polls that show the majority of Iranians disapprove of the government. In a speech on Saturday, Netanyahu urged the people of Iran to “stand up and let your voices be heard.”

“The time has come for you to unite around your flag and your historic legacy by standing up for your freedom from an evil and oppressive regime. It has never been weaker,” Netanyahu said. “Israel’s fight is not with you, the brave people of Iran whom we respect and admire. Our fight is with our common enemy, a murderous regime that both oppresses you and impoverishes you.”

Others said the focus of the military remained the nuclear facilities.

Regime change is not the primary goal of the Israeli operation against Iran, said Yossi Kuperwasser, a former senior Israeli military intelligence official, but he said if regime change were to occur in Iran, “nobody in Israel is going to complain.”

“We did carry out attacks today against regime facilities, especially those belonging to the Revolutionary Guard, but this is mostly in context of fighting the war, not in the context of bringing about the collapse of the regime,” he said.

Israeli attacks on Iran’s nuclear facilities overnight Thursday and on Friday damaged some of the aboveground infrastructure at the sites but did not appear to have eliminated enrichment centrifuges or enriched material buried deep underground, according to Post analysis of satellite imagery.

Iran responded to the stepped-up attacks by announcing a number of emergency response measures on Sunday. The Tehran metro system was ordered to stay open 24 hours so residents could use the stations as shelters overnight. Unlike Israeli cities, Iranian cities don’t have bomb shelters.

“Without exaggeration, we are in a state of war, a war that has been imposed on us. We did not want war and tried to prevent it,” said Fatemeh Mohajerani, an Iranian government spokesperson, according to a statement carried by state media. Mohajerani said Mosques and schools in Iranian cities were also ordered open to act as shelters, but it’s unclear what protection the buildings will provide if they are not underground.

The expansion of strikes to include energy infrastructure sent shock waves through Iran’s Persian Gulf neighbors and the oil markets they supply.

“This situation is very concerning,” Amena Bakr, a senior Middle East analyst with the shipping trade analytics firm Kpler. Because the South Pars gas field is shared with Qatar, she said, the attack was “an alarming sign of how close gulf assets are to the conflict.” So far, Bakr said, the strikes have only impacted Iran’s domestic energy production because the country doesn’t export gas from South Pars and Israeli strikes have spared infrastructure associated with oil exports. Global oil price shifts are “based on panic over what might happen, rather than a change in fundamentals,” she said.

Regardless of Israel’s larger war aims, the rapid expansion of targets in Iran demonstrates Netanyahu is prepared to move quickly, perhaps fearful the wide international latitude his operations have so far been granted could suddenly evaporate, according to Farzan Sabet, a researcher focusing on Middle East security at the Geneva Graduate Institute, a Swiss research institute.

“It’s not inevitable that this political space will always exist in terms of U.S. support and in terms of international pressure,” he said. “Now that they have air superiority and they have the political space to operate, they’re going to use it.”

Sabet said by targeting electronics, aviation and aerospace, Israel is attempting to focus on “bottlenecks in various key industries that support Iran’s nuclear, missile, drone, air defense industries.” And by striking critical industry, Israel is not only disarming Iran, but the attacks are also making it more difficult and more expensive for Iran to ever rearm, he said.

As the strikes picked up Sunday, Israel issued an order telling the Iranian people to move away from military installations. Many Iranians shot back with confusion in online posts. “Get away from military areas? We don’t know where they are!” one man wrote in an Instagram comment.

In Tehran, many decided the best way to respond to the order and the stepped-up strikes was to leave the city. The main roads leading out of the capital were choked with traffic Sunday, according to people on the roads interviewed by The Post. Iranian security forces set up checkpoints, and in at least one location a scuffle broke out between fleeing civilians and plainclothes Iranian officers.

Sharareh, 30 year-old housewife and mother of 5-year-old twins, said security forces at the checkpoints were harassing fleeing civilians as she and her family left Tehran to their vacation home outside the city.

“The raids are from the air and these nut-heads are looking into a normal citizen’s car on land to find Israeli spies. They are such fools,” she said. “On top of everything we are not safe from our own government either!”