Fighting that started a month ago between Sudan and South Sudan along the oil-rich Heglig region on the border has provoked increased repression in Sudan, noticeably on the media, report the Arabic Network for Human Rights Information (ANHRI), Human Rights Watch, Index on Censorship and the Committee to Protect Journalists (CPJ).
"Sudan is cracking down on civil and political rights in the face of conflict and opposition," says Daniel Bekele, Africa director at Human Rights Watch. "But locking up critics and silencing dissent will not solve Sudan's problems."
Here are some of the key ways that Sudan is silencing its critics.
Security officials have harassed and threatened journalists and political opposition members. In one high-profile example, National Intelligence and Security Service (NISS) officials summoned an independent Sudanese journalist and human rights defender, Faisal Mohamed Salih, to their office in Khartoum for several hours of questioning last month, report Human Rights Watch, ANHRI and CPJ.
Salih had criticised a speech by President Omar al-Bashir on Al Jazeera Arabic TV that expressed the President's desire to take over South Sudan. He was ordered to report back daily to NISS office, a strategy "to humiliate me and obstruct my work," Salih wrote in a statement about his ordeal.
After he refused to appear voluntarily, security officials went to his home and forced him to show up. He was then charged for refusing to cooperate with their orders. If convicted, he faces up to a month in jail.
"It is clear he is being targeted only because he criticised the government policies," Faisal al-Baqir, a Sudanese advocate for media freedom, told Human Rights Watch. "They want to deny him his right to talk."
Banning journalists from working
More than 15 journalists have been banned from working in recent months, a tactic that appears to be without an explicit legal basis, according to Human Rights Watch.
Last month, security officials summoned Haidar al-Mokashfi, a journalist for "Al-Sahafa", after he wrote an article about a church burning incident by followers of a radical local imam, reports Human Rights Watch. They banned him from working until he receives permission to resume his profession. As of 15 May, he was still waiting.
"Banning journalists from writing is a weapon used by the security agency to deprive journalists of their livelihoods and income in order to coerce them into obedience," says Abdelgadir Mohammed Abdelgadir, a Sudanese journalist writing for CPJ.
If NISS can't get to individual journalists, it applies pressure on their bosses. According to Abdelgadir, the security agency has been known to instruct management boards and newspaper editors to suspend certain journalists from writing. If the bosses don't comply, their papers face confiscation, possible suspension and even closure.
Under Sudanese law national security officials may ban a publication considered to be a threat to national security.
Since early May, NISS has confiscated more than 14 editions of different newspapers in Sudan for publishing articles critical of the government, says CPJ.
"By confiscating newspapers, the security agency aims to cause a significant financial loss and force the newspapers either to go out of business or to comply with its instructions," says Abdelgadir.
Authorities have also apparently resumed pre-print censorship, going to the publication's offices and ordering it to remove articles planned for the next edition, used intermittently in recent years, says Human Rights Watch.
Earlier this month, the newspaper "Al-Jarida" was so heavily censored that it suspended publication, reports Human Rights Watch.
Creating taboo topics
Sudan has identified about 20 taboo topics not to be tackled by the press, often "national issues that touch upon the future of the country," says Reem Abbas, a Sudanese journalist writing for Index on Censorship. The taboo topics include criticism of NISS, the armed forces, the police and the President, or references to threats to press freedom in the country. According to Abbas, "the list of banned topics grows every day."
In Kharthoum, security agents send a daily letter to editors-in-chief containing the list of "red lines". "The list of red lines is long and renewed on a daily basis," journalist Idris al-Douma, the managing editor of "Al-Jarida", told CPJ. "We usually abide by the directives of the security agency and have never disregarded them. Yet, the security agency still disrupts the printing of the newspaper," al-Douma said.
"If we publish an issue [of the newspaper] that is critical and includes topics the government is uncomfortable with - such as the conflicts in Blue Nile and Southern Kordofan - they punish us by confiscating our next issue," Adil Color, a writer and editor at "Al-Midan" newspaper, the mouthpiece of the Sudanese Communist Party (SCP), told Index.
Security agency censorship takes different forms, including orders communicated to the editor-in-chief or the managing editor in a short phone call not to publish about certain topics that the agency considers taboo.
"I received an evening phone call from the Intelligence and Security Services on 5 May," Madiha Abdullah, editor-in-chief of "Al-Midan", told CPJ. "However, we usually do not abide by these directives, as they are too numerous and restrictive and violate our right to publish and the people's right to access information." The paper's defiant attitude might explain why at the time of writing, it was confiscated for the eighth time this month alone, reports ANHRI.
The tabloid's byline now reads "daily newspaper, but temporarily published on Sunday, Tuesday and Thursday," says Index.
Arresting political opponents
On 21 April, security officials arrested Alawiya Osman Ismail Kibaida, a former health minister of Sennar state, and Ezdhar Juma, a lawyer and a former state minister, without revealing a reason, reports Human Rights Watch. Both women hold positions in Sudan People's Liberation Movement-North, the opposition party that emerged following the South's independence in July 2011.
The following day, security officials arrested seven other party members, who also remain in detention, says Human Rights Watch.
Under Sudanese law, NISS has broad powers to search, seize, arrest, and detain people for up to four and a half months without judicial review, in violation of international standards. The security service is known for using ill-treatment and torture against detainees.
"These detentions are shameful," Bekele said. "Authorities should immediate release or charge these people with a recognisable offence, and allow them access to a lawyer, family, and medical visits."