Thousands of Israelis have held a rally in the town of Beit Shemesh against ultra-Orthodox Jewish extremism.
The protest followed clashes after an eight-year-old girl said she had been harassed on her way to school.
Some ultra-Orthodox in Beit Shemesh are seeking to segregate men and women.
President Shimon Peres has backed the protest, saying the "entire nation must be recruited in order to save the majority from the hands of a small minority".
He said the demonstration was a defence of the "character" of the state of Israel "against a minority which breaks our national solidarity".
'Afraid to go to school'
Thousands of protesters gathered in Beit Shemesh, west of Jerusalem, on Tuesday evening.
They held signs "reading "Free Israel from religious coercion" and "Stop Israel from becoming Iran" - a reference to the Islamist republic's stringent restrictions on women's freedoms.
"This thing is really big and we're fighting for something really serious," one protester, Kinneret Havern told Reuters news agency.
The rally was addressed by opposition leader Tzipi Livni, who said the protesters were "fighting for the image of the state of Israel".
"It's not just Beit Shemesh and not just gender segregation, it's all the extremist elements that are rearing their heads and are trying to impose their worldview on us," she said.
In his statement, Mr Peres said: "No person has the right to threaten a girl, a woman or any person in any way."
Tensions have been growing in recent years between Israel's secular Jews and members of the ultra-orthodox Jews who seek an strict interpretation of religious laws.
In Beit Shemesh, where the communities live in close proximity, there have been regular protests by ultra-Orthodox men outside a religious girls school against what they say is the immodest dress of the children.
Anger spilled over after a documentary was broadcast on national TV in which one of the girls, eight-year-Naama Margolese, said she was afraid to walk to school in the town because ultra-Orthodox men shouted at her.
In October, her mother told the BBC the children were facing daily abuse which was giving them nightmares.
"Whenever she hears a noise she asks, 'are they there, are they out there?'," said Hadassah Margoleese.
Other women have reported similar incidents in the town of 100,000, some 18 miles (30km) south-west of Jerusalem.
Sarit Ramon described the situation in the town, where religiously observant immigrants live alongside Israelis embracing a more modern lifestyle, as having been "catastrophic for years".
Beit Shemesh resident Alisa Coleman told the BBC that she had been called a prostitute when dressed in a short-sleeved T-shirt and a skirt.
Though underlining that this behaviour was carried out by only a tiny proportion of the community, she said what was happening in Beit Shemesh was "a microcosm of what's happening in the whole country".
On Monday, one police officer was slightly hurt and a number of Orthodox Jews were detained after a group of some 300 ultra-Orthodox residents pelted police with stones and eggs in an incident reportedly triggered after police tried to remove a sign ordering segregation.
After the clashes, ultra-Orthodox activists from Beit Shemesh issued a statement condemning the violence, but also accusing the media of initiating "deliberate provocations in order to make the peaceful, quiet and tolerant residents, who live their lives according to their beliefs, look bad".
Such clashes have become more frequent in Israel in recent years as the authorities have challenged efforts by ultra-Orthodox Jews to segregate women in public places.
The BBC's Jon Donnison in Beit Shemesh says the events have highlighted what is a growing religious divide in Israel.
Ultra-Orthodox Jews make up 10% of the population in Israel. The community has a high birth rate and is growing rapidly.