By Eliza Mackintosh, CNN

(CNN) -- Five days after a 19-year-old Sudanese woman was sentenced to death for killing the man she was forced to marry, her lawyer was barred from holding a news conference amid an intensifying campaign of intimidation, activists told CNN.

Noura Hussein was imprisoned in Omdurman, Sudan, last year after fatally stabbing her husband, who she says raped her as his relatives held her down.

On Wednesday, Sudanese security forces came to the office of Hussein's lead attorney, Adil Mohamed Al-Imam, just hours before he was due to brief the media on the latest developments in the case, activists said.

"The National Intelligence Security Services 'NISS' banned the press conference and ordered Noura's defense team to cancel it," Nahid Gabralla, director of SEEMA, a non-governmental organization working with victims and survivors of gender-based violence in the capital, Khartoum, said in a statement.

Women's rights activist Amal Habani, coordinator of No Oppression Against Women Initiative Sudan, also confirmed that security forces came to Al-Imam's office Wednesday morning. Both Habani and and Gabralla were in touch with Al-Imam on Wednesday.

The Sudanese government has not responded to CNN requests for comment on the lawyer or the underlying case.

Activists and local journalists say it's the latest effort to prevent the media from reporting on the case and to intimidate Hussein's defense team. Her case has shone a spotlight on the issues of forced marriage and marital rape in Sudan, where the legal age of marriage is only 10 and marital rape is legal.

Her lawyers have until May 25 to appeal.

Activist: Hussein 'is still strong'

Gabralla last saw Hussein two days ago when she visited her at the women's prison in Omdurman.

"This is the first time I saw her after the sentence. She was wearing a long dress and shackles," Gabralla told CNN. "It is very hard for her. She was crying, but she is still strong and happy that people are supporting her case."

In Omdurman women's prison, a tight-knit sisterhood has formed around Hussein. Activists who have visited her there say that other inmates have rallied around her.

A group of activists trying to visit Hussein in prison were turned away on Tuesday, Amnesty International's Sudan researcher, Ahmed Elzobier, told CNN.

"There is a lot of pressure on the government, now that the EU, UN Women, and other agencies have issued a very strong statement," Elzobier said. "But unusually they (Sudanese government) have not issued a response. They're keeping their heads down amid all the exposure."

The European Union Delegation issued a statement on Hussein's case on Tuesday underlining their opposition to the death penalty and forced marriage. Amnesty International is petitioning for the Sudanese government to repeal the death penalty against Hussein, and allow her a retrial.

The harrowing details of Hussein's case have set social media and WhatsApp ablaze in Sudan. And in recent days the case has captured international attention with the hashtags #JusticeforNoura and #SaveNoura. Thousands of people have shared a change.org petition.

Forced to marry at 15, Hussein ran away from home and sought refuge with her aunt for three years. She was tricked into returning by her father, who handed her over to her husband's family.

After Hussein refused to consummate the marriage, her husband's relatives held her down while he raped her. "His brother and two cousins tried to reason with her, when she refused she was slapped and ordered into the room. One held her chest and head, the others held her legs," Al-Imam, her lawyer, told CNN last week.

A day later her husband tried to rape her again, and she stabbed him to death. When she went to her parents for support, they turned her in to the police.

Al-Imam said last week that the case has challenged societal expectations in Sudan that wives should submit to their husbands.

But it has also highlighted gaps in Sudan's national law, Elzobier said. "The good thing about this case is it brings up a lot of laws that need to change -- specifically rape and child marriage laws."

Gabralla agreed: "In my work I've seen other cases like this. The suffering of Sudanese women is happening all the time. But the case of Noura is different. She stood for her rights."