Algerian security forces have arrested dozens of people just two days after 22 people were killed in ethnic clashes between Berbers and Arabs in the country's south.

The country's prime minister on Thursday said that at least 27 people were arrested over what he said was their involvement in the violence in the Guerara district of the city of Ghardaia. Some media sources put the figure of those rounded up by security forces at 35.

The arrested included activist Kamal Fakhar al-Din, who has been campaigning for the rights of Berber people. He was in a mosque Ghardaia before security forces stormed it and arrested him and several other people.

Makeshift barricades of tyres and wheelbarrows were erected between the rival neighbourhoods and burned out homes, shops and cars, the AFP news agency reported on Thursday.

People want the army to maintain security but they are scared because they do not know what the security plan looks like.

Qassem Hajjaj, University of Ouargla

It also said that 16 of the dead were from the Berber community and three were Arabs.

Ghardaia is situated in the M'zab valley, a UNESCO world heritage site on the edge of the Sahara that has seen mounting tensions between the two communities.

There have been on-and-off confrontations between the two communities since December 2013 over property and land ownership after a Berber shrine was vandalised.

But this week's violence was the worst so far, prompting President Abdelaziz Bouteflika to order the regional commander general to "supervise the actions of the security services and local authorities to re-establish public order".

He also asked Prime Minister Abdelmalek Sellal to punish "all violations of the law with diligence and severity" and to ensure the security of people and their goods, his office said.

But some newspapers and analysts criticised the government's response.

Qassem Hajjaj, a doctor of political science at Algeria’s University of Ouargla, said that the security measures announced fail to address the roots of the tensions.

"The Berbers have economic grievances and they have not been compensated for the vandalism that was inflicted on their property during earlier clashes," he told Al Jazeera.

Berbers represent around 30 percent of the Algerian population and have long considered themselves marginalised by the country's dominant Arab culture.

"People want the army to maintain security but they are scared because they do not know what the security plan looks like," Hajjaj said.

He said people in Ghardaia are worried that security measures would restrain their movement and restrict their rights.

"There is fear of what is going to happen next. Local media, which are supposed to be an agent between the security officials and the residents, have not been informative at all."

Source: Al Jazeera and agencies