Some were veiled, others not, still more wrapped their faces in black-and-white checkered scarves. Most carried roses, Iraqi flags or signs defending their role in the regime change demonstrations.

They marched through a tunnel and spilled out into Tahrir Square, the epicentre of the youth-dominated movement in a country where vast regions remain socially conservative.

"We want to protect women's role in the protests as we're just like the men. There are efforts to kick us out of Tahrir but we'll only come back stronger," said Zainab Ahmad, a pharmacy student.

"Some people were inciting against us a few days ago, seeking to keep women at home or keep them quiet. But we turned out today in large numbers to prove to those people that their efforts will end in failure," she said.

Ahmad appeared to be referring to controversial cleric Moqtada Sadr, a powerful figure who first backed the rallies when they erupted in October but who has since sought to discredit them.

On Saturday, the militiaman-turned-politician had alleged drug and alcohol use among the protesters and said it was immoral for men and women to mix there.

And a few moments before Thursday's women's march began, Sadr once again took to Twitter to slam the protests as being rife with "nudity, promiscuity, drunkenness, immorality, debauchery... and non-believers".

In a strange turn, he said Iraq must not "turn into Chicago," which he said was full of "moral looseness" including homosexuality, a claim that was immediately mocked online.

Sadr, who has a cult-like following of millions across Iraq, has faced unprecedented public criticism in recent weeks for his dizzying tweets on the protests.

- 'Freedom, revolution, feminism' -

While the numbers in Tahrir have dwindled in recent weeks, many Iraqi youth say the past four months of rallies have helped break down widespread conservative social norms.

Men and women were seen holding hands in Tahrir and even camping out in the square together.

On Thursday, men linked arms to form a protective ring around the women as they marched for over an hour.

"Revolution is my name, male silence is the real shame!" they chanted, then adding "Freedom, revolution, feminism!"

Some of their chants were snide remarks at Sadr himself.

"Where are the millions?" some said, referring to the cleric's call for a million-strong march several weeks ago that saw much smaller numbers hit the streets.

The rallies have slammed Iraqi authorities for being corrupt, incompetent and beholden to neighbouring Iran.

"They want us to be a second Iran, but Iraqi women weren't born to let men dictate to them what to do," protester Raya Assi told AFP on Thursday.

"They have to accept us the way we are."

Other rallies took place in Basra, a stronghold for traditional tribal influences that have long limited women's role in the public sphere.

"The revolution is female," read a handwritten sign carried by an older woman in a black veil and a medical mask, to protect her from tear gas.