Sudan's Prime Minister Abdalla Hamdok has called for calm ahead of a "million-strong" march to demand the implementation of the "goals of the revolution" that ousted long-serving leader Omar al-Bashir last year.
"You will be hearing consecutively in the coming days a number of key decisions for the course of the transitional period. Some of them could have a major political, economic, and social effect," the premier said in a national address Monday night.
Activists are calling for the formation of a transitional parliament, the appointment of civilian regional governors and a reform of the country's security agencies.
The protests are also taking place in the midst of soaring food prices and fuel shortages.
The authorities have barricaded the main roads in the capital Khartoum and deployed heavily towards the army headquarters, according to the local media.
On Monday, government spokesman Faisal Mohamed Saleh said the authorities arrested nine agents from the old regime as they prepared to carry out "hostile activities". It is not clear whether the arrests are related to the protests.
Sudan also arrested former foreign minister and leader of the defunct National Congress Party (NCP) Ibrahim Ghandour ahead of protests but no reason was given, the private al-Sayha newspaper said.
The party had said it will not take part in today's protests, which also mark the anniversary of the coup that brought Bashir into power.
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