More than 800 protesters have been arrested in anti-government demonstrations held across Sudan since last month, a senior government minister has said.

"The total number of protesters arrested until now is 816," Interior Minister Ahmed Bilal Osman told parliament on Monday.

The figure was the first given by officials for those detained since the rallies erupted in towns and villages and later spread to the capital, Khartoum.

On Sunday, several faculty members of Khartoum University were arrested for joining the protest that started on December 19 over a government decision to raise the price of bread.

The mass protests pose a serious challenge to President Omar al-Bashir, who has ruled the country since 1989.

Sudan has been facing a mounting economic crisis over the past year led by an acute shortage of foreign currency while the cost of food items and medicines has more than doubled and inflation has hit 70 percent.

Al-Bashir has pledged to address the issues facing the people in the North African nation but that has failed to convince the protesters.

Authorities say at least 19 people, including two security personnel, have been killed in clashes during the demonstrations, but rights group Amnesty International has put the death toll at 37.

Osman said that 118 buildings were destroyed in the protests, including 18 that belonged to the police, while 194 vehicles were set on fire including 15 that belonged to international organisations.

"The demonstrations began peacefully, but some thugs with a hidden agenda used them to indulge in looting and stealing," the minister said, adding that the situation across Sudan was now "calm and stable".

Pro-Bashir rally

Several buildings and offices of the ruling National Congress Party (NCP) were torched in the initial violence.

Sudanese authorities have launched a crackdown on opposition leaders, activists and journalists to prevent the spread of protests.

Most anti-government rallies have been spearheaded by professionals such as doctors, teachers and engineers, but they have been swiftly broken up by riot police firing tear gas at protesters.

On Monday, crowds of protesters gathered in the Red Sea city of Port Sudan but they were quickly dispersed by riot police, witnesses said.

As the anti-government unrest rumbled on, the first rally backing al-Bashir was held in the eastern city of Kassala.

Hundreds of people from Kassala and neighbouring towns and villages gathered in front of the local governorate to express their support for al-Bashir.

Several supporters were carrying banners that read "Bashir, we want you to stay", witnesses said.

"We want Bashir as president in order to maintain security in the country," Mohameddin Issa, a resident of Kassala participating in the rally told AFP news agency by telephone.

"Security is the top priority, after that comes food...but I also believe that the problem of food will be solved soon."