ASHDOD, Israel — Throngs of shoppers trundled through the stores of the Big Fashion Mall on a recent Saturday afternoon, enjoying what is a typical weekend pastime in most parts of the world — but here, an act of defiance.

Mayor Yehiel Lasri has already sent his municipal inspectors to fine businesses at the mall that open Saturday, the Jewish day of rest.

Now, after the Israeli parliament passed a law last month aimed at enforcing Sabbath closures everywhere in the country, Saturday shopping at Big Fashion could soon be a thing of the past.

The simple act of perusing shops on a Saturday has turned Ashdod, the country’s sixth-largest city, into the latest flash point in a 70-year struggle between religious and secular Jews over the character of Israel.

While Israeli law has long barred work on the Sabbath, known as Shabbat, it also bent far enough to allow places of entertainment to operate so that nonobservant families could enjoy their day off.

More recently, in response to consumer demand, some stores have opted to open on Saturdays, with shop owners willing to pay often-symbolic fines as a cost of business.

Then, last fall, the struggle between the religious and secular escalated suddenly when the ultraliberal city of Tel Aviv petitioned the Israeli Supreme Court to let that city’s bylaws, allowing business to operate on Saturdays, override the national prohibition.

After a senior judge ruled in favor of Tel Aviv, ultra-Orthodox leaders who hold key positions in Prime Minister Benjamin Netanyahu’s government responded by pushing through a bill to close stores. The measure was dubbed by the media as the “minimarkets law.”

Meir Berger, an ultra-Orthodox — or Haredi — resident of Ashdod and a reporter for the national Haredi newspaper Hamevaser, said it was only a matter of time before tension in the city over Shabbat ignited.

“We didn’t really want this war, but with local elections coming up soon, it was bound to make some noise,” said Berger. “The Haredi leadership both locally and nationally feels that if it does not fight to protect Israel’s Jewish symbols, then no one will.”

He said the ultra-Orthodox had made some tough compromises in the religious-secular battle over Shabbat, allowing for movie theaters, bowling alleys and restaurants to open.

“But once you start allowing commercial centers to operate, too, there is nothing left of Israel’s Jewish character,” he said.

Big Fashion — a collection of local and international chain stores, restaurants, cafes and artificial waterfalls — opened in this coastal city three years ago, and Saturdays soon became its busiest day, drawing Israelis from far and wide.

Half an hour’s drive south of Tel Aviv, Ashdod prides itself on being a melting pot of Jewish immigration. But the influx of Jews from all over the world, with wildly different customs and beliefs, is producing friction among the opposing communities.

Alongside veteran Israelis, who see themselves as traditionally secular, a significant population of Russian speakers calls the city home. They arrived from the countries of the former Soviet Union about 20 years ago, and although they are proud of their Jewish heritage, their stores are far from kosher, selling bacon and shellfish.

Their presence has challenged the city’s sizable ultra-Orthodox population, who demand the closing of all businesses and services from sundown Friday to sundown Saturday. They have pressured the mayor to take on the Big Fashion Mall — especially if he wants to remain mayor after the next local elections.

But Lasri’s efforts at pressuring shops to close has stirred ire among secular residents, who have been apathetic about local politics. Thousands have turned out for weekly demonstrations against what many see as religious coercion.

“We want to live in a democratic state. We want Shabbat the way we like it,” said Rosa Milevsky, 52, who came out to protest on a recent Saturday night with her friend Julia Kopilov. “The only day we have to go out with our families is Saturday. We want to see everything open.”

Shmuelik Duek warned that Ashdod would end up like other cities in Israel, where he said the Haredim have imposed their way of life on the secular. He mentioned Beit Shemesh, where a few years ago ultra-Orthodox Jews clashed with other residents over the opening of a school in their neighborhood. A Haredi man was called out in the secular media for spitting at an 8-year-old girl and calling her a whore. It shocked much of the nation.

“We don’t want that to happen here,” Duek said.

But another Ashdod resident, an ultra-Orthodox man who declined to be named because of the sensitivity of the issue, said it was not about religious coercion.

“It is about maintaining the status quo and respecting the law,” said the man, who has been involved in lobbying the mayor to close businesses on Shabbat. “In my neighborhood, a city swimming pool is open on Shabbat. I am not demanding that it be closed because the law allows for places of entertainment to be open. It does not allow for commercial businesses to be open.”

Even before Israel’s establishment in 1948, observant Jews argued that in the world’s only Jewish state, Saturday should be a day of rest — at least for the country’s Jewish residents. Israel’s founding prime minister, David Ben-Gurion, agreed to make Saturday a formal day of rest.

But in a letter sent to leading rabbis in 1947, Ben-Gurion said there was “no intention of establishing a theocratic state.”

Ben-Gurion’s letter is what most Israelis use as the basis for what they call the religious-secular status quo.

In ruling in favor of Tel Aviv’s court petition, Judge Miriam Naor waded into the middle of the dispute over the meaning of the religious-secular status quo in modern Israel. She noted that “while protecting the special character of Shabbat, every individual must be allowed to formulate his Shabbat in accordance with his own path and his beliefs, and fill it with content that is appropriate for himself.”

Angered by the ruling, the influential leader of the ultra-Orthodox Shas party, Aryeh Deri — who is also Netanyahu’s interior minister — drafted legislation ramping up his own powers to override local authorities.

Israel Cohen, editor of the ultra-Orthodox news website Kikar HaShabbat, said Ashdod has now become a test case for the law.

“The truth is the Haredim don’t really care about Tel Aviv. They have accepted it is a liberal, secular city. But if this law is successfully enforced in Ashdod, then other cities will follow,” he said.