Veteran Sudanese journalist Mahjoub Mohamed Saleh says he cannot remember a time when there were so many “red lines” – invisible boundaries that the media cross at their peril.

“You don’t know what the red lines are,” said Saleh, who started his career in 1949 when Britain still ruled Sudan and is now editor of Sudan’s oldest newspaper, Al-Ayam.

“Sometimes you are told ‘don’t publish this’ but they (the red lines) keep moving.”

Reporters in Sudan have long known that criticising the president or writing about official corruption could bring a beating or jail. Official censorship ensured journalists knew exactly where the lines were.

But censorship was abolished in 2009, and the secession of South Sudan a year ago and recent border fighting with the new nation has worsened the situation for press freedom.

Interviews with Southern officials or rebels in the borderlands, which the government says are supported by Juba, are taboo.

New topics that reporters should not touch come up all the time, and punishment for crossing the line is increasingly financial – withdrawal of advertising or blocking the distribution of newspapers.

Last week, the authorities confiscated an edition of Al-Ahram Al-Youm to stop it publishing an interview with Pagan Amum, South Sudan’s top official in peace talks with Sudan, its editor said.

“I can say without hesitation that this is the worst time I have faced as a journalist in 60 years,” said Saleh.

Sudan ranks 170th of 179th in a global press freedom index.

As tension with South Sudan escalates and an economic crisis bites, pressure is mounting on journalists to be “patriotic”.

The security services have suspended three newspapers this year after they criticised the government, editors say. Several reporters have been banned from writing.

“Sometimes you get a phone call not to tackle this or that,” said Alnoor Ahmed Alnoor, editor of the independent daily Al-Sahafa. “Often you don’t know what they object to because you don’t get it in writing.”

Bashir declared an amnesty for all imprisoned journalists in August. But several reporters have not been released or still face charges.

Reporters also say they face random summoning by security agents.

When journalist Faisal Mohamed Saleh criticised Bashir on Al Jazeera television for calling South Sudan’s rulers “insects”, he was detained and grilled for hours. With no legal case, they let him go but ordered him to return every morning for 11 days.

“Every day I sat in a room there with nobody talking to me. I sat there until the evening and came back the next morning,” he said.

The government says press freedom is guaranteed in Sudan’s constitution and that reporters face no problems if they comply with the law.

“We have more than 30 newspapers … that publish daily, and I don’t think there is any monitoring or controlling of them,” said Rabie Abdelati, an information ministry spokesman.

But editors say Sudan authorities suppress coverage by blocking entire editions after they have been printed.

The government has stopped the distribution of communist newspaper Midan, which often attacks the government, for 20 days, its editor Madiha Abdallah said.

The security service could not be reached for comment. Experts say it has vast powers under a media code of conduct that requires journalists to defend Sudan’s “interest, unity, survival and integrity”.

“This stipulation has been used by … agents to criminalise freedom of expression, including restricting reporting on armed conflicts in Sudan,” Amnesty International said.

Critics say the authorities withhold advertising, either by government agencies or by the companies in which they have stakes. – Reuters