They came for the men first, as the security forces of Syria's President Bashar al-Assad killed, beat and arrested people protesting against his regime.

Next, they came for the women of Syria's revolution. Despite the threats, however, they refuse to be silenced.

As the violence has become worse, women activists have organised a Friday protest of Free Women showing solidarity with those seized or killed. Women-only protests in towns across the country have led the effort to let the outside world know what is happening in Syria. But they are now being targeted as well, with the same lethal brutality.

Two weeks ago three women were shot dead at an all-women march near the besieged city of Banias. A week later human rights activist Catherine al-Talli, 32, was detained in the Barzeh district of Damascus after being forced off a minibus when it was stopped at a checkpoint by the secret police.

Others, such as Razan Zeitouneh, whose husband has been arrested, have been forced into hiding as evidence emerges that the regime is targeting relatives of those it is seeking to arrest.

Yesterday it was Zeitouneh who reported that the final death toll for the latest crackdown on Friday protests by the regime had been 30. Twelve were reported dead in Ma'aret al-Nu'man, south of the city of Aleppo, after tanks entered the town earlier in the day to disperse protesters; 11 in the central city of Homs and seven in Deraa, Latakia, the Damascus suburbs and Hama.

"Reem" – we have changed her name to protect her family – spoke to the Observer from Syria last week. Aged 22, she is expecting her first child in the next few weeks. Her husband, an anti-regime activist, has been arrested twice and is now in detention. Her father was invited to a meeting with a senior member of the regime and detained afterwards.

Reem has been arrested once. In common with activist friends, she expects a knock on her door from the security forces at any moment. She is still ready to risk prison by talking about the murderous repression in her country.

"I have women friends who have been arrested like me," she said. "But then they just go out again to protest. One of my friends was arrested for collecting medical supplies for the people in Deraa. She was beaten at the security branch and they forced her to take off her headscarf. She was held for two weeks and released two days ago.

"She is very enthusiastic and active. She is getting ready to protest again. The only thing that is keeping me at home right now is that I'm expecting a baby in two weeks."

For now, Reem has to content herself with reporting what she has seen and what she knows, which is dangerous enough in a country where the international media are largely banned. "If you tell the truth," she said, "there is a big chance of arrest. You risk being beaten and being treated with no dignity."

That treatment was described last week by Dorothy Parvaz, an al-Jazeera journalist who was arrested by the Syrians in Damascus and encountered a number of terrified young women in the security barracks where she was held. Upon her release, Parvaz described how two of the young women she met had simply been plucked off the street for no apparent reason. "One had been there for eight days when I met her," wrote Parvaz last week. "And she looked ill. The food we were given three times a day – fetid, random and at times rotting – mostly had the effect of making her vomit, but she was too hungry to stop eating."

Reem has an explanation for the detention of these young women. "They have been arresting anyone with a phone they see in the streets," she said. "They do not want anyone to take pictures, to tell the world what is happening."

Reem describes seeing one young woman being dragged by security forces into a shop at a demonstration. "We saw a young girl and some security men in civilian clothes. They grabbed her by the head and dragged her off, calling her a traitor. She said: 'I'm not a traitor!' They pulled her into a shop and we tried to reach her, but they shut the door on us and then took her somewhere else.

"Women have played a really important role since the first protests in March – non-violent activists like myself and the mothers and sisters of prisoners of conscience."

And the part women are playing has become ever more important. "In some areas," says Ameera, a human rights lawyer, "so many of the men have been killed, arrested or injured it is the women who have been left to protest. The biggest problem is trying to find the people who have disappeared. The security forces won't say where they are, and the families are afraid to speak out."

For some – like Ameera – the threat has succeeded in persuading them to stay at home. She now feels unable to protest. "It feels like you are waiting for your turn to be arrested. I am expecting to be arrested at any moment. I am not scared for myself, but I am afraid for my family."