Algeria was mobilising the army on Thursday after 22 people were killed in the worst ethnic clashes between Berbers and Arabs in years, as more details emerged of the violence.
The fighting erupted late on Tuesday in the town of Guerara in the M'zab valley, a UNESCO world heritage site on the edge of the Sahara that has seen mounting tensions between its Berber and Arab communities.
An AFP photographer who toured the town on Thursday saw makeshift barricades of tyres and wheelbarrows erected between the rival neighbourhoods and burned out homes, shops and cars.
After crisis talks on Wednesday, President Abdel Aziz Bouteflika ordered the army to restore order across the province but the AFP photographer saw no troop reinforcements yet deployed in Guerara.
A Berber leader told AFP that 16 of the dead were from his community and three were Arabs.
The two communities are divided not only by language but also by religion.
The Mozabite Berbers are followers of the Ibadi faith, an austere form of Islam that predates the split between Sunnis and Shiites.
The Chaamba Arabs, like the majority of Algerians, are Sunnis.
Algerian newspapers gave harrowing accounts of the violence on Thursday, with El Watan daily speaking of "hordes" of masked gunmen who went on a killing and arson spree.
El Watan said the gunmen rode through town on motorcycles, forcing residents out of homes which they later torched as policemen failed to intervene.
El Khabar newspaper said masked men carrying hunting rifles opened fire in the streets, drawing out residents they then mowed down.
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 Bouteflika to summon Prime Minister Abdelmalek Sellal and army chief General Ahmed Gaid Salah for emergency talks.
'Ancestral values'
Bouteflika ordered regional commander General Cherif Abderrezak to "supervise the actions of the security services and local authorities to re-establish public order".
He also asked 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.
Sellal, speaking during a visit to the affected province of Ghardaia on Thursday, said the government was determined to take "appropriate and firm action to end all forms of violence and restore peace in the region".
He added that the army had "all the necessary powers to re-establish order" and could even impose a curfew or ban demonstrations and gatherings.
But some newspapers and analysts criticised the government's response.
La Tribune newspaper complained that each time there was a flare-up in the M'zab the government announced security measures but failed to address the underlying causes of the tensions.
An editorialist said the failure reflected a wider crisis in Algeria, where "the specificity of a region and its ancestral values" tend to be ignored by authorities.
Berbers represent around 30 percent of the Algerian population and have long considered themselves marginalised by the country's dominant Arab culture.
Guerara is a modern town but the M'zab is famed for five ancient fortified hilltop towns built by the Berbers nearly 1,000 years.
It is their traditional architecture and way of life that earned the whole region its UNESCO listing.
Professor Rostom El Djazairia, a Mozabite Berber, said in an opinion piece published by El Watan on Thursday that his community was being marginalised by the authorities.
In a harshly-worded article he spoke of a "plan to asphyxiate an entire population" and of a "well-structured bid to isolate it morally and politically".
The government was seeking "to dictate by means of threats and terror… to the Mozabite community the terms of its submission," he charged.
