Sexual violence is increasingly being used as a "weapon of war" in Sudan to terrorise the civilian population, a UN report says.
The violence is "unprecedented in terms of the scale, prevalence and brutality of its widespread use as a weapon of war", the report adds.
Sudan has been hit by a devastating civil war since 2023, following a fallout between the army the paramilitary Rapid Support Forces (RSF).
Meanwhile, the UK and six other European powers have added their voice to calls for an immediate halt to violence in el-Obeid city as fears grow that the RSF is preparing for a major assault to capture it.
UK Foreign Secretary Yvette Cooper warned the city was on the "precipice of atrocity", with the RSF using drones to target civilian infrastructure, attacking supply routes and cutting off access to basic services for over half a million people.
"There are now credible signs of an imminent offensive. This is a critical moment, and the international community must act," said a joint statement issued by the UK, France, Germany, Ireland, Italy, the Netherlands and Norway.
In its report, the UN Human Rights Office said it had verified 546 incidents of conflict-related sexual violence, including gang-rape and sexual slavery, in Sudan since the war started more than three years ago.
It affected at least 838 victims - 539 women, 284 girls, eight men and seven boys.
The figures represent "only the tip of the iceberg", as "persistent under-reporting has obscured the full scale of the prevalence of sexual violence", the report said.
Most of the verified cases were attributed to fighters in the RSF and allied militias, but the army and its allies were also accused of carrying out sexual violence, the report added.
UN human rights chief Volker Türk said that sexual violence was being used as a "weapon of war".
"This is a war crime and, if committed as part of a widespread or systematic attack, a crime against humanity," he added.
The RSF and army have not yet commented on the report -but both have denied such allegations in the past.
The fighting has led to the world's worst humanitarian crisis with more than 11 million people forced from their homes and 28 million facing acute hunger, aid agencies say.
