While missile alerts and piercing sirens have become a regular occurrence for Israelis since the conflict started 11 days ago, a few happy revellers have been getting the party started in bomb shelters converted into night clubs.

"Dancing in difficult times is a relief. It gives us strength," said Ruben Chekroun, one of the organisers of these semi-clandestine dance nights.

"It's hard right now, so we might as well try to make the best of it," he told AFP.

The war erupted on February 28, when the United States and Israel bombarded Iran with heavy missile fire, killing supreme leader Ali Khamenei.

Tehran responded with drone and missile strikes on Israeli and US interests across the region.

Chekroun, a French-Israeli, was among a group of friends visiting Tel Aviv for the Jewish holiday of Purim when they got stranded as the conflict shut down flights.

As the threat of attacks saw nightlife in the usually party-loving commercial hub grind to a halt, they decided they were not going to let the fun stop.

"Stuck because of the war, unable to go out at night, we ended up spending our days on the beach and came up with this great idea for partying safely," said one of the group, Ilan Eber, his cap on backwards.

"We did a bit of advertising on social media, and it just went crazy!"

Four "bunker parties" were held in places such as underground parking lots that have been specially designated as bomb shelters.

While strictly speaking the events seem to contravene restrictions imposed on mass gatherings, they have been tolerated by the authorities.

"The police came each time. Now they understand that we're not doing anything wrong," Elber said.

For the first time, that night's festivities were being held in the basement of a nightclub off the usually buzzing Dizengoff Street that had been shut until then.

"It's just like being in a shelter. If there's a siren, we're protected from the bombing," said one of the clubbers, giving only her nickname "Goldilocks".

"It's the place to be!"

- 'Business as usual' -

While Israel's state-of-the-art air defences have managed to largely protect the country from Iran's barrages, Tel Aviv has been repeatedly targeted.

On the first day of the war, a woman in her forties was killed by missile fire, which wounded some 20 others in the bloodiest incident there so far.

Despite the threat, during the day the vibe remains laid-back in a city known for the cultivated cool of its hipster atmosphere.

Shirtless joggers run along the Mediterranean seafront and yoga sessions are held near the beach.

A street away, at "Chacho's" cafe, customers in sunglasses sip lattes and matcha tea.

"It's been business as usual for us, we stay calm," said the smiling waitress, an octopus tattoo curling up her forearm.

"As soon as the alerts stop, customers immediately return."

Like many Israelis, they have long adjusted to the heightened threat level since the October 7, 2023 attack by Hamas set off the war in Gaza.

"We get like five to 10 alerts a day," said Owen, refusing to give his surname.

Shortly afterwards, mobile phones beeped in unison as a missile alert came in and the wail of sirens started up.

Chacho's clients got up and headed calmly towards the nearest shelter -- a school basement next door complete with a table football, giant chess set and collection of Harry Potter books.

Several muffled booms were heard in the distance. Then the all-clear was given and people headed back to what they were doing.

Soon the news came of casualties some 10 kilometres (six miles) north of Israel's main airport Ben Gurion.

Two construction workers hit by shrapnel were killed, taking the total death toll across Israel to 12 since the war started.