Women and girls are being increasingly caught up in Colombia's armed conflict, as rival groups rape, mutilate and kill them, Amnesty International says.
Female members of the armed group are also vulnerable to abuse
Amnesty accuses Colombia's security forces, rebels and paramilitaries of using sexual violence to sow terror.
In a "macabre twist" in the conflict, armed groups are even punishing women for wearing cropped tops and low-slung jeans, says the human rights group.
Amnesty is urging Colombia's leaders to act to tackle the abuse.
Women and girls have been victims of violence throughout Colombia's 40 years of civil conflict.
But now, Amnesty says, the armed groups are not merely terrorising communities, they are imposing punitive codes of conduct on entire towns and villages.
"[The right-wing paramilitaries] told girls they mustn't wear cropped tops and low-slung jeans," one inhabitant of Cartagena told Amnesty.
"The boy were banned from having long hair or wearing earrings...a young woman had acid put in her belly button."
Amnesty, in its report "Scarred Bodies, Hidden Crimes: sexual violence against women in the armed conflict," details several cases of violence.
Armed men raped and killed a pregnant 16-year-old, ripping her stomach open in front of other villagers. Another woman told how she was raped by a guerrilla from the main left-wing group Farc.
"He raped me and told me that it was a little reminder...not to get mixed up with soldiers."
Women and girls have been kidnapped by the armed groups as sexual slaves for the commanders, Amnesty reports.
Female recruits also face sexual abuse by fellow combatants.
The sexual violence has appalling consequences for the victims, Amnesty's UK campaigns director Stephen Bowen said.
"They are often rejected by their family, humiliated by the legal system, refused medical care, and rarely see their attacker brought to justice," Mr Bowen said.
The group is calling on the Colombian government to prosecute those responsible and ensure adequate care for victims.
Amnesty also wants the international community to put pressure on the government and armed groups to end violence against women and to ensure that no military aid or arms supplies contribute to human rights violations.