Residents of Tehran have fled the Iranian capital in large numbers in the face of Israeli bombardments, creating immense traffic jams on the main road heading north, according to social media content posted on Monday.

Images verified by AFP, shot by a social media user from an overpass, showed near-immobile traffic on a northbound Tehran highway with almost no vehicles in the opposite lane.

Israel on Friday launched a surprise aerial campaign targeting nuclear and military sites across Iran, saying the attacks aimed to prevent the Islamic Republic from acquiring nuclear weapons amid signs that its nuclear program had accelerated significantly.

The Israeli strikes have so far killed at least 224 people, including top military commanders and nuclear scientists, but also civilians, according to Iranian authorities.

Retaliatory Iranian ballistic missile strikes have rained down on Israel, concentrated mainly in the north and center of the country, killing 24 people and injuring hundreds.

Iranian authorities have closed civilian airspace until further notice due to the Israeli attacks, leaving land routes the only way out of Tehran, which has been heavily targeted.

Israel has warned Iranians to stay away from any military infrastructure in a city where the security forces maintain a heavy presence, both overt and covert.

State TV broadcast scenes of collapsed presidential buildings, burned-out cars and shattered streets in Tehran. Many residents describe long lines for gas and ATMs that were out of cash.

“I am desperate. My two children are scared and cannot sleep at night because of the sound of air defense and attacks, explosions. But we have nowhere to go. We hid under our dining table,” Gholamreza Mohammadi, 48, a civil servant, told Reuters by phone from Tehran.

Videos filmed inside Iran and posted by Persian-language TV channels based abroad, such as Iran International and Manoto, as well as widely followed bloggers including Vahid Online, showed long rows of cars barely moving as they tried to leave Tehran.

The congestion appeared to be concentrated on Highway 49, which connects Tehran with Chalus on the Caspian Sea in the Mazandaran province.

The region, about 150 kilometers (90 miles) north of Tehran and typically a three-hour drive even in normal times due to the mountain roads, has so far been largely spared.

It is popular with Tehranis for its mild climate, with many maintaining holiday homes there.

Persian-language outlets, meanwhile, posted images of hundreds of cars lining roads outside gas stations in Tehran and its satellite city of Karaj, saying they were filling up ahead of long journeys outside of the city.

Art teacher Arshia, 29, told Reuters his family was leaving Tehran for the town of Damavand, around 30 miles (50 kilometers) to the east, until the conflict was over.

“My parents are scared. Every night, there are attacks. No air raid sirens, and no shelters to go to. Why are we paying the price for the Islamic Republic’s hostile policies?” said Arshia, who withheld his surname for fear of reprisal from authorities.

While air travel is impossible, Iranians can still, in theory, cross borders by land to go abroad, and footage on social media showed hundreds waiting at the Gurbulak-Bazargan crossing point in western Iran with Turkey, close to the eastern Turkish city of Dogubayazit.

At the border crossing, Shirin Talebi was anxiously waiting for her children and grandchildren to arrive from Tehran. The family were planning to stay for a month or two in Turkey, seeking temporary refuge from the conflict between Israel and Iran.

“I’m here because of safety. They are bombing. My children have small children of their own,” said Talebi, who had just arrived at the crossing from the Iranian city of Urmia.

“Hopefully, it is over in one or two months so we can return to our country,” she said.

Turkey, which shares a 348-mile-long (569 kilometers) border with Iran, has expressed deep concern over the escalating conflict across the border, with fears that prolonged fighting could threaten its security, cause energy disruptions and lead to refugee flows.

Observers have noted an increase in arrivals from Iran since the conflict, though Turkish officials have dismissed social media reports of a large-scale refugee influx as unfounded. Turkey has not provided any official figures for arrivals.

“Our Ministry of Interior and relevant security units confirm that there is no unusual movement, congestion or irregular crossing at both the Kapıkoy and Gurbulak border gates,” the Turkish presidential communications office said.

Turkey allows Iranians to enter the country without a visa for tourism purposes and stay for up to 90 days.

At Gurbulak, one of the busiest crossings between Turkey and Iran, bus driver Ferit Aktas had just brought a group of Iranians to the border gate from Istanbul and was waiting to pick up others.

“About a week or 10 days ago, there would be between three and five people [Iranians] who would come for shopping or tourism. But now, I can say, that there are at least 30 Iranians in my vehicle per day,” he said.

“They say, ‘We are not safe there and we are forced to come.’ Most of them want to go to Europe, they want to go to Europe through Turkey,” Aktas said.

Mejid Dehimi, also from Umria, arrived in Turkey for a week-long break, not to escape the conflict. He expressed support for his country’s leaders.

“We are not afraid of death,” he said. “We will stand against Israel until our last breath and for as long as our lives allow.”