They are fighting the world's most feared extremists, but hundreds of Arab female fighters battling the "Islamic State of Iraq and the Levant" (ISIL) in Syria are also confronting the disapproval of their relatives and society.

Batul, 21, is part of an Arab-Kurdish alliance battling to capture ISIL's Syrian stronghold of al-Raqa.

She is one of more than 1,000 Arab women who have joined Kurdish male and female fighters in the Syrian Democratic Forces (SDF) alliance, according to a spokeswoman.

Standing in the desert some 20 kilometres from al-Raqa, Batul speaks passionately about her decision to fight ISIL, which holds the nearby village of al-Torshan.

She says she is proud of the decision she took two years ago to join the YPJ, the female counterpart to the Kurdish People's Protection Units, which is a key component of the SDF alliance.

"I joined the YPJ to liberate my homeland, but also to free women from slavery," she says.

"We must no longer remain cloistered behind four walls."

'My weapon is part of me'

Syrian Kurds and Arabs have been fighting ISIL since late 2015, with air support and other backing from the international coalition against the group.

But the current battle for al-Raqa is the first time Batul has been on the front line, where warplanes roar overhead carrying out strikes, and mortars boom in the distance.

"The first time I held a weapon, I was very afraid," she admits.

"But now, my weapon has become part of me. It frees me and protects me."

She speaks in Arabic, but her sentences are peppered with Kurdish words picked up from her fellow fighters.

"The relations between us and the Kurdish women are good. We do not speak the same language, but we are all here to free the country and women."

Jihan Sheikh Ahmad, spokeswoman for the campaign on al-Raqa, said the SDF now counts more than 1,000 Arab women in its ranks.

"The YPJ's experience has had a positive impact on society," she told AFP.

"The more territory we liberate, the more Arab female fighters have joined us."

In a tent near the front line, six young Arab female fighters joke and share secrets as they sip tea.

'Same rights as men'

"My goal is to liberate women from the oppression of ISIL, but also societal oppression," says Hevi Dilirin, an Arab woman who adopted a Kurdish nom de guerre when she joined the YPJ.

"In our society, women have no say. But they should have the same rights as men," she says, dressed in a camouflage jacket and white-and-grey sneakers.

Syria's Kurds have emphasised gender equality in both their militias and nascent institutions.

But the Arab tribes there are among the more conservative segments of the population, and 21-year-old Doza Jiyan says most Arab families find the concept of female fighters "hard to accept".

"In our Syrian society, we find it bizarre for a woman to take up arms," adds Jiyan, from the town of Ras al-Ain in Hasakeh province.

But she speaks confidently as she discusses the military situation with male colleagues.

"ISIL is no longer invincible, they are only fighting on motorbikes and mining the villages," she says.

ISIL's extensive use of IEDs and mines has slowed the SDF's progress towards al-Raqa, the group's most important remaining bastion in Syria.

The SDF announced a new phase in their bid to capture al-Raqa on February 4th, pressing towards the city gradually from the north and north-east.

Jiyan is convinced that the SDF's military successes will eventually sway the opinion of her relatives and society, and she has no plans to leave.

"I am very happy here," she says.