Amnesty International said the sentencing of a woman to death for "killing her rapist husband in self-defence" highlighted the "failure of the authorities to tackle child marriage, forced marriage and marital rape".
Sodfa Daaji tweeted "The court is full".
Noura Hussein Hammad, 19, was handed a death sentence by a court on Thursday for the "intentional murder" of the man her father forced her to marry. Al-Imam donated his services after Hussein's original lawyer withdrew from the case. Over 140,000 people have also signed a petition to help her, which you can sign here.
Hussein refused to accept it, running away to live with a relative in a neighbouring city for almost three years, according to Amnesty International and other activists involved in her case.
Hammad fled to her family home after the incident but her father handed her to the police, Amnesty said.
Reports say her husband's family rejected financial compensation and insisted on retribution forcing the presiding judge to pronounce death penalty for Noura.
After six days she says he recruited some of his cousins who allegedly held her down as he raped her.
Campaign groups such as Equality Now say they are writing to Sudanese President Omar al-Bashir to plead for clemency, arguing that the judgement is against the Sudanese constitution. Hussein was forced to marry at age 15, and subsequently ran away from her home.
Shahd Hamza, 20, was among those who came to support Hussein in court, after hearing about her case in a group chat on WhatsApp.
"The case of Noura is different".
Sudan is marked 165 out of 188 in the United Nations Development Programme's Gender Development Index, which quantifies gender inequality using income levels, political representation, reproductive health, maternal mortality rates and other measures.
Marital rape and child marriage, for example, are not considered crimes in the predominately Muslim African nation.
Because Noura was a victim of rape, many are calling for her release, and for her not to be punished at all.
Magango, of Amnesty International, said that by applying the "cruel" death penalty to a rape victim, Sudanese authorities failed to acknowledge the violence Hussein endured.