Sudanese security officers seized the print runs of 14 newspapers on Monday, a government-run media body said, in one of the most sweeping crackdowns on the press in recent years.
The National Intelligence and Security Service seized copies of 14 dailies, Sudan's press council said in a statement.
The council, a government body overseeing the country's media, held an emergency meeting and expressed "its deep regret at this step to block this large number of newspapers".
NISS often confiscates print runs of newspapers over stories it deems unsuitable but it rarely seizes so many publications at one time.
Sudanese media watchdog Journalists for Human Rights said the move "represents an unprecedented escalation by the authorities against freedom of the press and expression".
The authorities gave no reason for the confiscation, the editor of one of the seized newspapers said.
"After the printing was finished, security officers arrived and seized all printed copies without giving any reason for that," Osman Mirghani, editor of Al-Tayar, said.
Information Minister Ahmed Bilal Osman said the newspapers were "seized in accordance with the law" but also gave no reason for the move.
Reporters Without Borders expressed its concern, saying in a statement: "Today, RSF is all the more preoccupied as it's almost all the press of the day that was gagged."
"Khartoum often uses seizures of print copies of newspapers, not only to censor the media but also to weaken them economically," said Clea Kahn-Sriber, RSF's head of Africa desk.
Around 50 journalists held a sit-in outside the press council in protest at the confiscation, dispersing peacefully an hour later.
Sudan regularly ranks near the bottom of international press freedom indexes.
The newspapers seized were Al-Tayar, Al-Rai al-Aam, Al-Intibaha, Akhir Lahza, Al-Ahram al-Youm, Awal al-Nahar, Al-Watan, Al-Sudani, Alwan, Al-Saiha, Al-Mijhar al-Siyasi, Al-Dar, and Hikayat, Journalists for Human Rights said.
Newspaper vendors said the Akhbar al-Youm daily was the final title seized.